Title of Invention	COMPRESSOR DIAGNOSTIC SYSTEM
Abstract	A compressor assembly comprising: a compressor; an electric motor attached to said compressor for powering said compressor; a thermal protector associated with said motor, said motor protector actuatable between a first portion when said motor is within specified operating parameters, and a second position when said motor is outside of said specified operating parameters; and characterized in that: a compressor diagnostic system associated with said motor protector, said diagnostic system being able to diagnose a compressor assembly problem based upon the status of said motor protector.

Title of Invention

COMPRESSOR DIAGNOSTIC SYSTEM

Abstract

A compressor assembly comprising: a compressor; an electric motor attached to said compressor for powering said compressor; a thermal protector associated with said motor, said motor protector actuatable between a first portion when said motor is within specified operating parameters, and a second position when said motor is outside of said specified operating parameters; and characterized in that: a compressor diagnostic system associated with said motor protector, said diagnostic system being able to diagnose a compressor assembly problem based upon the status of said motor protector.

Full Text	COMPRESSOR DIAGNOSTIC SYSTEM FIELD OF THE INVENTION [0001] The present invention relates to a diagnostic system for a compressor. More particularly, the present invention relates to a diagnostic system for a refrigeration or air-conditioning system which uses the compressors "trip" information to diagnose the problems associated with the system. BACKGROUND AND SUMMARY OF THE INVENTION [0002] A class of machines exists in the art generally known as scroll machines which are used for the displacement of various types of fluid. These scroll machines can be configured as an expander, a displacement engine, a pump, a compressor, etc. and the features of the present invention are applicable to any of these machines. For purposes of illustration, however, the disclosed embodiment is in the form of a hermetic refrigerant scroll compressor used within a refrigeration or air conditioning system. [0003] Scroll compressors are becoming more and more popular for use as compressors in both refrigeration as well as air conditioning applications due primarily to their capability for extremely efficient operation. Generally, these machines incorporate a pair of intermeshed spiral wraps, one of which is caused to orbit relative to the other so as to define one or more moving chambers which progressively decrease in size as they travel from an outer suction port toward a center discharge port. An electric motor is provided which operates to drive the orbiting scroll member via a suitable drive shaft affixed to the motor rotor. In a hermetic compressor, the bottom of the hermetic shell normally contains an oil sump for lubricating and cooling purposes. While the diagnostic system of the present invention will be described in conjunction with a scroll compressor, it is to be understood that the diagnostic system of the present invention can be used with other types of compressors also. [0004] Traditionally, when an air conditioning or refrigeration system is not performing as designed, a technician is called to the site for trouble shooting the problem. The technician performs a series of checks that assists in isolating the problem with the system. One of the causes of the system's problem could be the compressor used in the system. A faulty compressor exhibits some operational patterns that could be used to detect the fact that the compressor is faulty. Unfortunately, many other causes for system problems can be attributed to other components in the system and these other causes can also affect the performance of the compressor and its operational pattern. It is possible to analyze the system's problems and operational patterns and determine that the compressor is faulty when in fact the problem lies elsewhere and the compressor is not the problem. This confusion of causes usually results in the replacement of a good compressor. This error in diagnosis is costly since the compressor is generally the most expensive component in the system. Further aggravating the problem is that the root cause for the system's problem has not solved and the problem recurs in time. Any tool which can help avoid the misdiagnosing of the system's problem as described above would prove both useful and cost effective. The present invention discloses a device that increases the accuracy of the problem diagnosis for an air conditioning or refrigeration system. [0005] A large part of the compressors used in air conditioning and refrigeration systems have built-in protection devices called "internal line break protectors". These protectors are thermally sensitive devices which are wired in electrical series with the motor. The protectors react thermally to the line current drawn by the motor and also other temperatures within the compressor including but not limited to discharge gas temperature, suction gas temperature or temperature of a particular component in the compressor. When one of these temperatures exceeds a designed threshold, the protector will open the electrical connection to the motor. This shuts down the motor operating the compressor which in turn shuts down the compressor and prevents it from operating in regions that would lead to its failure. After a period of time, when the temperatures have fallen to safe levels, the protector automatically resets itself and the compressor operates again. The temperatures that the protector is reacting to are a result of the operation of the compressor and the entire system. Either the operation of the compressor or the operation of the entire system can influence the temperatures sensed by these protectors. The significant aspect of the protection system is that some categories of faults repeatedly trip the protector with very short compressor ON time and other categories of faults trip the protector less frequently thus providing relatively longer compressor ON times. For example, a compressor with seized bearings would trip the protector within about ten seconds of ON time. On the other hand, a system that has a very low refrigerant charge will trip the protector after tens of minutes of ON time. An analysis of the trip frequency, trip reset times and compressor ON times will provide valuable clues in identifying the cause of the system's problems. [0006] The present invention provides a device which is based on this principle. The device of the present invention continuously records the status of the protector (open or closed) as a function of time and then it analyzes this status information to determine a faulty situation. The device goes further and isolates the fault to either the compressor or to the rest of the system. Once the fault has been isolated, the device will activate a visual indicator (light) and it will also send an electrical signal to any intelligent device (controller, computer, etc.) advising about the situation. The technician, on arriving at the scene, then has a clear indication that the problem is most likely in the system components other than the compressor or the problem is most likely in the compressor. He can then focus his further trouble shooting to the identified area. The device thus avoids the previously described situation of a confused diagnosis and the potential of mistakenly replacing a good compressor. [0007] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for Durposes of illustration only and are not intended to limited the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0009] Figure 1 is a vertical cross section of a hermetic scroll compressor incorporating the unique compressor diagnostic system in accordance with the present invention; [0010] Figure 2 is a schematic representation of the diagnostic system for a single phase motor for the compressor in accordance with the present invention; [0011] Figure 3 is a schematic representation of a diagnostic system for a three phase motor for the compressor in accordance with another embodiment of the present invention; [0012] Figure 4 is a flow diagram of the diagnostic system for the single phase motor for the compressor in accordance with the present invention; [0013] Figure 5 is a flow diagram of the diagnostic system for the three phase motor for the compressor in accordance with the present invention; [0014] Figure 6 is a flow diagram which is followed when diagnosing a compressor system; [0015] Figure 7 is a schematic view of a typical refrigeration system utilizing the compressor and diagnostic system in accordance with the present invention; [0016] Figure 8 is a perspective view of a contactor integrated with the diagnostic system's circuitry in accordance with another embodiment of the present invention; [0017] Figure 9 is a schematic view illustrating the circuitry of the contactor illustrated in Figure 8; and [0018] Figure 10 is a schematic view of a compressor plug which illustrates the diagnostic system's circuitry in accordance with another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0019] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. [0020] Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in Figure 1 a scroll compressor incorporating the unique compressor diagnostic system in accordance with the present invention and which is designated generally by the reference numeral 10. While compressor 10 is being illustrated as a scroll compressor in conjunction with a refrigeration or air conditioning system, it is within the scope of the present invention to utilize other types of compressors in the refrigeration or air conditioning system if desired as well as having any of the compressor designs being in conjunction with other types of systems. [0021] Scroll compressor 10 comprises a generally cylindrical hermetic shell 12 having welded at the upper end thereof a cap 14 and at the lower end thereof a base 16 having a plurality of mounting feet (not shown) integrally formed therewith. Cap 14 is provided with a refrigerant discharge fitting 18 which may have the usual discharge valve therein. A transversely extending partition 20 is affixed to shell 12 by being welded about is periphery at the same point that cap 14 is welded to shell 12. A compressor mounting frame 22 is press fit within shell 12 and it is supported by the end of base 16. Base 16 is slightly smaller in diameter than shell 12 such that base 16 is received within shell 12 and welded about its periphery as shown in Figure 1. [0022] Major elements of compressor 10 that are affixed to frame 22 include a two-piece main bearing housing assembly 24, a lower bearing housing 26 and a motor stator 28. A drive shaft or crankshaft 30 having an eccentric crank pin 32 at the upper end thereof is rotatably journaled in a bearing 34 secured within main bearing housing assembly 24 and a second bearing 36 secured within lower bearing housing 26. Crankshaft 30 has at the lower end thereof a relatively large diameter concentric bore 38 which communicates with a radially outwardly positioned smaller diameter bore 40 extending upwardly therefrom to the top of crankshaft 30. The lower portion of the interior of shell 12 defines an oil sump 44 which is filled with lubricating oil to a level slightly above the lower end of a rotor, and bore 38 acts as a pump to pump lubricating fluid up crankshaft 30 and into bore 40 and ultimately to all of the various portions of compressor 10 which require lubrication. [0023] Crankshaft 30 is rotatably driven by an electric motor which includes stator 28, windings 46 passing therethrough and a rotor 48 press fitted into crankshaft 30. An upper counterweight 50 is secured to crankshaft 30 and a lower counterweight 52 is secured to rotor 48. A temperature protector 54, of the usual type, is provided in close proximity to motor windings 46. Thermal protector 54 will de-energize the motor if thermal protector 54 exceeds its normal temperature range. Thermal protector 54 can be heated by motor windings 46, suction gas within a suction chamber 56 and/or discharge gas within a discharge chamber 58 which is released into suction chamber 56. Both suction chamber 56 and discharge chamber 58 are defined by shell 12, cap 14, base 16 and partition 22 as shown in Figure 1. [0024] The upper surface of two-piece main bearing housing assembly 24 is provided with a flat thrust bearing surface on which is disposed an orbiting scroll member 60 having the usual spiral vane or wrap 62 extending upward from an end plate 64. Projecting downwardly from the lower surface of end plate 64 of orbiting scroll member 60 is a cylindrical hub 66 having a journal bearing therein and which is rotatably disposed a drive bushing 68 having an inner bore in which crank pin 32 is drivingly disposed. Crank pin 32 has a flat on one surface which drivingly engages a flat surface formed in a portion of the inner bore of drive bushing 68 to provide a radially compliant driving arrangement, such as shown in Assignee's U.S. Letters Patent 4.877.382, the disclosure of which is hereby incorporated herein by reference. An Oldham coupling 70 is also provided positioned between orbiting scroll member 60 and two-piece bearing housing assembly 24. Oldham coupling 70 is keyed to orbiting scroll member 60 and to a non-orbiting scroll member 72 to prevent rotational movement of orbiting scroll member 60. [0025] Non-orbiting scroll member 72 is also provided with a wrap 74 extending downwardly from an end plate 76 which is positioned in meshing engagement with wrap 62 of orbiting scroll member 60. Non-orbiting scroll member 72 has a centrally disposed discharge passage 78 which communicates with an upwardly open recess 80 which is in turn in communication with discharge chamber 58. An annular recess 82 is also formed in non-orbiting scroll member 72 within which is disposed a floating seal assembly 84. [0026] Recesses 80 and 82 and floating seal assembly 84 cooperate to define axial pressure biasing chambers which receive pressurized fluid being compressed by wraps 62 and 74 so as to exert an axial biasing force on non- orbiting scroll member 72 to thereby urge the tips of respective wraps 62 and 74 into sealing engagement with the opposed end surfaces of end plates 76 and 64, respectively. Floating seal assembly is preferably of the type described in greater detail in Assignee's U.S. Letters Patent 5,156,639, the disclosure of which is hereby incorporated herein by reference. Non-orbiting scroll member 72 is designed to be mounted for limited axial movement with respect to two-piece main bearing housing assembly 24 in a suitable manner such as disclosed in the aforementioned U.S. Letters Patent 4,877,382 or Assignee's U.S. Letters Patent 5,102,316, the disclosure of which is hereby incorporated herein by reference. [0027] Compressor 10 is powered by electricity which is provided to the electric motor within shell 12 through a molded electric plug 90. [0028] Referring now to Figures 1 through 3, the present invention is directed to a unique compressor diagnostic system 100. Diagnostic system 100 comprises one or more current sensing devices 102 and the associated logic circuitry 104. Current sensing devices 102 are mounted in a housing 106 mounted externally to shell 12. Logic circuitry 104 can be mounted in housing 106 or it can be located in a convenient position with respect to compressor 10 as shown in phantom in Figure 2. Optionally, the sensing device and circuitry can be integrated into a special contactor, a special wiring harness or into a molded plug utilized for some compressor designs. [0029] Current sensing devices 102 sense the current in the power supply wires powering compressor 10. Figure 2 illustrates two current sensing devices 102 in conjunction with a single-phase motor. One of the current sensing devices 102 is associated with the main windings for the compressor motor and the other current sensing device 102 is associated with the auxiliary windings for the compressor motor. Figure 3 also illustrates two current sensing devices 102 in conjunction with a three phase motor. Each current sensing device 102 is associated with one of the phases of the three phase power supply. While Figure 3 illustrates two current sensing devices sensing current in two phases of the three phase power supply, it is within the scope of the present invention to include a third current sensor 102 to sense the current in the third phase of the three phase power supply as shown in phantom in Figure 3 if desired. These current signals represent an indication of the status of protector 54 (open or closed). While current sensing devices 102 sense the status of protector 54 utilizing the current in the power supply wires, it is also possible to sense the status of protector 54 by sensing the presence or absence of voltage on the motor side of protector 54. The inventors of the present invention consider this to be a less desirable but effective approach in some cases because it requires an additional hermetic feed-through pin extending through shell 12. The signals received from current sensing devices 102 are combined in logic circuitry 104 with the demand signal for compressor 10. The demand signal for compressor 10 is acquired by sensing the presence of supply voltage or by having a system controller (not shown) supply a discrete signal representing the demand. The demand signal and the signal received by logic circuitry 104 are processed by logic circuitry 104 to derive the information about the trip frequency of protector 54 and the average ON time and OFF time of compressor 10. Logic circuitry 104 analyses the combination of current signals, the demand signal and the derived protector trip frequencies to determine if a fault condition exists. Logic circuitry also has the unique capability of identifying a specific cause based on some faults. This information is provided to the service people using a green LED light 110 and a yellow LED light 112. Green LED light 110 is utilized to indicate that there is currently no fault condition and that the system is functioning normally. [0030] Yellow LED light 112 is utilized to indicate the presence of a fault. When yellow LED light 112 is turned ON, green LED light 110 is turned OFF. Thus, yellow LED light 112 is utilized to visually communicate that there is a fault as well as indicating the type of fault that is present. This communication is accomplished by turning yellow LED light 112 ON and then OFF for a specific duration and sequence to indicate both that there is a fault and to identify what the fault is. For example, turning light 112 ON for one second and turning it OFF for nineteen seconds and repeating this sequence every twenty seconds will create the effect of a blinking light that blinks ON once every twenty seconds. This sequence corresponds to a type of fault that is coded as a type 1 fault. If light 112 is blinked ON twice for one second during the twenty second window, it is an indication that a fault that is coded as a type 2 is present. This sequence continues to indicate a type 3, a type 4 and so on with the type of fault being indicated by the number of blinks of light 112. This scheme of the blinking of light 112 for a specific number of times is employed to visually communicate to the technician the various types of faults detected by logic circuitry 104. While the present invention utilizes blinking light 112 to convey the fault codes, it is within the scope of the present invention to utilize a plurality of lights to increase the effectiveness of conveying a large number of fault codes if desired. In addition, other methods of providing the default code, including providing a coded voltage output that can be interfaced with a Digital Volt Meter, can also be employed. [0031] In addition to visually communicating the specific fault code using light 112, logic circuitry 104 also outputs a coded sequence of electrical pulses to other intelligent controllers that may exist in the system. These coded pulses represent the type of fault that has been detected by diagnostic system 100. The types of faults which can be detected by logic circuitry 104 include, but are not limited to: 1. Protector has "tripped". 2. The auxiliary winding of a single phase motor has no power or is open or has a faulty run capacitor. 3. The main winding of a single phase motor has no power or that the winding is open. 4. The main circuit breaker has contacts that have welded shut. 5. One of the phases in a 3 phase circuit is missing. 6. The phase sequence in a 3 phase system is reversed. 7. The supply voltage is very low. 8. The rotor inside the compressor has seized. 9. The protector is tripping due to system refrigeration circuit problems. 10. The motor windings are open or the internal line break protector is faulty. [0032] As a variation to the above, as shown in Figure 3, diagnostic system 100 may only send the status of protector 54 to an intelligent device 116. In this option, the parameters of trip frequencies, ON times and OFF times with the diagnosis information may be generated at intelligent device 116. Intelligent device 116 can be a compressor controller associated with compressor 10, it can be a system controller monitoring a plurality of compressors 10, it can be a remotely located device or it can be any other device which is selected to monitor diagnostic system 100 of one or more compressors. [0033] Figure 4 represents a flow diagram for diagnostic system 100 in conjunction with a single phase compressor. The demand signal is provided to logic circuitry 104 from a device or a contactor 120 (Figures 2 and 3) along with the current signal from sensing devices 102. When the system is initially powered up, an initializing process is performed at 122 and, if successful, the system, as shown by arrow 124, goes to a normal OFF condition as shown at 126. When sitting at the normal OFF condition 126, if a demand signal is provided to the system, the system moves as shown by arrow 128 to a normal run condition shown at 130. Once the demand has been met, the system returns to the normal OFF condition 126 as shown by arrow 132. [0034] While sitting at the normal OFF condition 126, if current in the main winding or current in the auxiliary winding is detected and there has been no demand signal, the system moves as shown by arrow 134 to a shorted contactor condition 136. While indicating the shortened contactor condition 136, if the demand is signaled, the system moves as shown by arrow 138 to the normal run condition 130. The normal run condition 130 continues until the demand has been satisfied where the system moves as shown by arrow 132 back to the normal OFF condition 126 which may again move to the shortened contactor condition 136 depending on whether or not current is sensed in the main or auxiliary windings. [0035] While operating in the normal run condition 130, one of three paths other than returning to the normal OFF condition 126 can be followed. First, if the system senses demand and main winding current but does not sense auxiliary winding current, the system moves as shown by arrow 140 to an open auxiliary circuit condition 142. From here, the system moves to a protector tripped condition 144 as shown by arrow 146 when both a main winding current and an auxiliary winding current are not sensed. Second, if the system senses demand and auxiliary winding current but does not sense main winding current, the system moves as shown by arrow 148 to an open main circuit condition 150. From here, the system moves to the protector tripped condition 144 as shown by arrow 152 when both a main winding current and an auxiliary winding current are not sensed. Third, if the system senses demand and does not sense auxiliary winding current and main winding current, the system moves as shown by arrow 154 to the protector tripped condition 144. [0036] While operating in the protector tripped condition 144, one of four paths can be followed. First, if main winding current or auxiliary winding current is sensed and the demand is satisfied, the system moves as shown by arrow 160 to the normal run condition 130. Second, with the protector tripped, and the moving window average of the ON time of the system has been less than twelve seconds, the system moves as shown by arrow 162 to a multiple short run condition 164. From the multiple short run condition, the system moves back to the protector tripped condition 144 as shown by arrow 166. Third, with the protector tripped, and the moving window average of the ON time of the system has been greater than fifteen minutes, the system moves as shown by arrow 168 to a multiple long run condition 170. The system moves back to the protector tripped condition 144 as shown by arrow 172. Fourth, with the protector tripped, if the tripped time exceeds four hours, the system moves as shown by arrow 174 to a power loss or protector defective condition 176. If, while the system is in the power loss or protector defective condition 176 and main winding current or auxiliary winding current is sensed, the system moves back to the protector tripped condition 144 as shown by arrow 178. [0037] When the system moves to the various positions shown in Figure 4, the blinking of light 112 is dictated by the fault condition sensed. In the preferred embodiment, if a protector tripped condition is sensed at 154 because demand is present but current is missing, light 112 blinks once. If compressor 10 is seized or there is a low supply voltage problem such as indicated by arrow 162 because the average ON time during the last five trips was less than twelve seconds, light 112 blinks twice. If the motor windings are open, the protector is faulty or the contactor is faulty as indicated by arrow 174 because the OFF time is greater than four hours, light 112 blinks three times. If the auxiliary windings are open or there is a faulty run capacitor as indicated by arrow 140, light 112 blinks four times. If the main winding is open as indicated by arrow 148, light 112 blinks five times. If the contactor is welded as indicated by arrow 134 because current is sensed but there is no demand, light 112 blinks six times. Finally, if there are repeated protector trips due to other system problems as indicated by arrow 168 because the average ON time during the last five trips was less than fifteen minutes, light 112 blinks seven times. [0038] Figure 5 represents a flow diagram for diagnostic system 100 in conjunction with a three phase compressor. The demand signal is provided to logic circuitry 104 from contactor 120 (Figures 2 and 3) along with the current signal from sensing devices 102. When the system is initially powered up, an initializing process is performed at 122 and, if successful, the system, as shown by arrow 124, goes to a normal OFF condition as shown at 126. When sitting at the normal OFF condition 126, if a demand signal is provided to the system, the system moves as shown by arrow 128 to a normal run condition shown at 130. Once the demand has been met, the system returns to the normal OFF condition 126 as shown by arrow 132. [0039] While sitting at the normal OFF condition 126, if current in one of the three phases or current in a second of the three phases is detected and there has been no demand signal the system moves as shown by arrow 234 to a shorted contactor condition 136. While indicating the shortened contactor condition 136, if the demand is signaled, the system moves as shown by arrow 238 to the normal run condition 130. The normal run condition 130 continues until the demand has been satisfied where the system moves as shown by arrow 132 back to the normal OFF condition 126 which may again move to the shortened contactor condition 136 depending on whether or not current is sensed in the main or auxiliary windings. [0040] While operating in the normal run condition 130, one of three paths other than returning to the normal OFF condition 126 can be followed. First, if the system senses demand and eleven milliseconds is less than the zero crossing time difference between the first and second phases of the three phase power supply or this time difference is less than fourteen milliseconds, the system moves as shown by arrow 240 to a phase sequence reversed condition 242. From here, the system moves to a protector tripped condition 144 as shown by arrow 246 when both a first phase current or a second phase current is not sensed. Second, if the system senses demand and sixteen milliseconds is less than the zero crossing time difference between the first and second phases or this time difference is less than twenty-one milliseconds, the system moves as shown by arrow 248 to a phase missing condition 250. From here, the system moves to the protector tripped condition 144 as shown by arrow 252 when both a first phase current and a second phase current are not sensed. Third, if the system senses demand and does not sense first phase current and second phase current, the system moves as shown by arrow 254 to the protector tripped condition 144. [0041] While operating in the protector tripped condition 144, one of four paths can be followed. First, if first phase current or second phase current is sensed and the demand is satisfied, the system moves as shown by arrow 260 to the normal run condition 130. Second, with the protector tripped, and the moving window average of the ON time of the system has been less than twelve seconds, the system moves as shown by arrow 162 to a multiple short run condition 164. From the multiple short run condition, the system moves back to the protector tripped condition 144 as shown by arrow 166. Third, with the protector tripped, and the moving window average of the ON time of the system has been greater than fifteen minutes, the system moves as shown by arrow 168 to a multiple long run condition 170. The system moves back to the protector tripped condition 144 as shown by arrow 172. Fourth, with the protector tripped, if the tripped time exceeds four hours, the system moves as shown by arrow 174 to a power loss or protector defective condition 176. If, while the system is in the power loss or protector defective condition 176 and first phase current or second phase current is sensed, the system moves back to the protector tripped condition 144 as shown by arrow 278. [0042] When the system moves to the various positions shown in Figure 5, the blinking of light 112 is dictated by the fault condition sensed. In the preferred embodiment, if a protector tripped condition is sensed at 254 because demand is present but current is missing, light 112 blinks once. If compressor 10 is seized or there is a low supply voltage problem such as indicated by arrow 162 because the average ON time during the last five trips was less than twelve seconds, light 112 blinks twice. If the motor windings are open, the protector is faulty or the contactor is faulty as indicated by arrow 174 because the OFF time is greater than four hours, light 112 blinks three times. If the contactor is welded as indicated by arrow 234 because current is sensed but there is no demand, light 112 blinks four times. If there are repeated protector trips due to other system problems as indicated by arrow 168 because the average ON time during the last five trips was less than fifteen minutes, light 112 blinks five times. If the power supply phases are reversed as indicated by arrow 240 because the zero crossing time difference is between eleven and fourteen milliseconds, light 112 blinks six times. Finally, if there is a phase missing in the three phase power supply as indicated by arrow 248 because the zero crossing time difference is between sixteen and twenty-one milliseconds, light 112 blinks seven times. [0043] While the above technique has been described as monitoring the moving window averages for compressor 10, it is within the scope of the present invention to have logic circuitry 104 utilize a real time or the instantaneous conditions for compressor 10. For instance, in looking at arrows 162 or 168, rather than looking at the moving window average, logic circuitry 104 could look at the previous run time for compressor 10. [0044] Figure 6 represents a flow diagram which is followed when diagnosing a system problem. At step 300, the technician determines if there is a problem by checking the LEDs at step 302. If green LED 110 is lit, the indication at 304 is that compressor 10 is functioning normally and the problem is : with other components. If yellow LED light 112 is blinking, the technician counts the number of blinks at 306. Based upon the number of blinks of light 112 the determination of the failure type is made at 308. The fault is corrected and the system is recycled and started at 310. The system returns to step 300 which again will indicate any faults with compressor 10. [0045] Thus, diagnostic system 100 provides the technician who arrives at the scene with a clear indication of most likely where the problem with the system is present. The technician can then direct his attention to the most likely cause of the problem and possibly avoid the replacement of a good compressor. [0046] Figure 7 illustrates a typical refrigeration system 320. Refrigeration system 320 includes compressor 10 in communication with a condensor 322 which is in communication with an expansion device 324 which is in communication with an evaporator 326 which is in communication with compressor 10. Refrigerant tubing 328 connects the various components as shown in Figure 7. [0047] Referring now to Figure 8, a contactor 120 is illustrated which incorporates diagnostic system 100 in the form of current sensors 102, logic circuitry 104, green LED light 110 and yellow light 112. Contactor 120.is designed to receive information from various system controls such as a system thermostat 350 (Figures 2 and 3), a group of system safeties 352 (Figures 2 and 3) and/or other sensors incorporated into the system and based upon three inputs provide power to compressor 10. [0048] Contactor 120 includes a set of power-in connectors 354, a set of power-out connectors 356, a set of contactor coil connectors 358, light 110 and light 112. The internal schematic for contactor 120 is shown in Figure 9. A power supply 360 receives power from connectors 354, converts the input power as needed and then supplies the required power to input circuitry 362, processing circuitry 364 and output circuitry 366, which collectively form logic circuitry 104. [0049] Input circuitry 362 receives the input from current sensors 102 and the demand signal in order to diagnose the health of compressor 10. The information received by input circuitry 362 is directed to processing circuitry 364 which analyses the information provided and then provides information to output circuitry 366 to operate compressor 10 and/or activate LED lights 110 and 112. The incorporation of logic circuitry 104 into contactor 120 simplifies the system due to the fact that both the line power and the demand signal are already provided to contactor 120. The function and operation of diagnostic system 100 incorporated into contactor 120 is the same as described above for housing 106. [0050] Referring now to Figure 10, molded plug 90 is illustrated incorporating diagnostic system 100 in the form of current sensors 102, logic circuitry 104, light 110 and light 112. In some applications, incorporation of diagnostic system 100 into molded plug 90 offers some distinct advantages. When diagnostic system 100 is incorporated into molded plug 90, power is provided through connectors 354 and must also be provided to diagnostic system from the input power or it can be provided separately through connector 370. In addition, the demand signal must also be provided to plug 90 and this can be done through connectors 372. The function and operation of diagnostic system 100 incorporated into molded plug 90 is the same as described above for housing 106. Communication from plug 90 is accomplished through connection 374. [0051] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. We Claim: 1. A compressor assembly comprising: a compressor; an electric motor attached to said compressor for powering said compressor; a thermal protector associated with said motor, said motor protector actuatable between a first portion when said motor is within specified operating parameters, and a second position when said motor is outside of said specified operating parameters; and characterized in that: a compressor diagnostic system associated with said motor protector, said diagnostic system being able to diagnose a compressor assembly problem based upon the status of said motor protector. 2. The compressor assembly as claimed in claim 1, wherein said diagnostic system includes an indicator which shows the status of said motor protector. 3. The compressor assembly as claimed in claim 2, wherein said diagnostic system includes an indicator which identifies a specific problem. 4. The compressor assembly as claimed in claim 1, wherein said diagnostic system includes an indicator which shows a system problem. 5. The compressor assembly as claimed in claim 1, wherein said diagnostic system monitors when said compressor is operating and when said compressor is idle. 6. The compressor assembly as claimed in claim 5, wherein said diagnostic system monitors the length of time said motor protector stays in said second position. 7. The compressor assembly as claimed in claim 1, wherein said diagnostic system monitors the length of time said motor protector stays in said second position. 8. The compressor assembly as claimed in claim 1, wherein at least one current sensor is provided for determining said status of said motor protector. 9. The compressor assembly as claimed in claim 8, wherein a demand signal is provided, said demand signal in conjunction with said status of said motor protector being used to diagnose said compressor problem. 10. The compressor assembly as claimed in claim 1, wherein a demand signal is provided, said demand signal in conjunction with said status of said protector being used to diagnose said compressor problem. 11. The compressor assembly as claimed in claim 1, wherein an electric plug is provided, said diagnostic system being integrated into said electrical plug. 12. The compressor assembly as claimed in claim 1, wherein a contactor is provided, said diagnostic system being integrated into said contactor. 13. A cooling system comprising: a condensor; an expansion device in communication with said condensor; and a compressor assembly as claimed in the preceding claims. 14. The compressor assembly as claimed in claim 13, wherein at least one current sensor is provided for determining said status of said motor protector. 15. The compressor assembly as claimed in claim 14, wherein a demand signal is provided, said demand signal in conjunction will said status of said motor protector being used to diagnose said compressor problem. 16. The compressor assembly as claimed in claim 13, wherein a demand signal is provided, said demand signal in conjunction with said status of said motor protector being used to diagnose said compressor problem. 17. The compressor assembly as claimed in claim 13, wherein an electrical plug is provided, said diagnostic system being integrated into said electrical plug. 18. The compressor assembly as claimed in claim 13, wherein a contactor is provided, said diagnostic system being integrated into said contactor. 19. The compressor assembly as claimed in claim 13, wherein a thermal motor protector is provided, said electric circuitry being able to sense a status of said motor protector. 20. The compressor assembly as claimed in claim 19, wherein said electronic circuitry includes at least one current sensor. 21. The compressor assembly as claimed in claim 13, wherein said electronic circuitry includes at least one current sensor. 22. The compressor assembly as claimed in claim 13, wherein said electronic circuitry comprises a compressor diagnostic system able to diagnose a problem with said compressor assembly. Dated this 18th day of March 2002. A compressor assembly comprising: a compressor; an electric motor attached to said compressor for powering said compressor; a thermal protector associated with said motor, said motor protector actuatable between a first portion when said motor is within specified operating parameters, and a second position when said motor is outside of said specified operating parameters; and characterized in that: a compressor diagnostic system associated with said motor protector, said diagnostic system being able to diagnose a compressor assembly problem based upon the status of said motor protector.

Full Text

COMPRESSOR DIAGNOSTIC SYSTEM
FIELD OF THE INVENTION
[0001] The present invention relates to a diagnostic system for a
compressor. More particularly, the present invention relates to a diagnostic
system for a refrigeration or air-conditioning system which uses the compressors
"trip" information to diagnose the problems associated with the system.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] A class of machines exists in the art generally known as scroll
machines which are used for the displacement of various types of fluid. These
scroll machines can be configured as an expander, a displacement engine, a
pump, a compressor, etc. and the features of the present invention are
applicable to any of these machines. For purposes of illustration, however, the
disclosed embodiment is in the form of a hermetic refrigerant scroll compressor
used within a refrigeration or air conditioning system.
[0003] Scroll compressors are becoming more and more popular for
use as compressors in both refrigeration as well as air conditioning applications
due primarily to their capability for extremely efficient operation. Generally, these
machines incorporate a pair of intermeshed spiral wraps, one of which is caused
to orbit relative to the other so as to define one or more moving chambers which
progressively decrease in size as they travel from an outer suction port toward a
center discharge port. An electric motor is provided which operates to drive the

orbiting scroll member via a suitable drive shaft affixed to the motor rotor. In a
hermetic compressor, the bottom of the hermetic shell normally contains an oil
sump for lubricating and cooling purposes. While the diagnostic system of the
present invention will be described in conjunction with a scroll compressor, it is to
be understood that the diagnostic system of the present invention can be used
with other types of compressors also.
[0004] Traditionally, when an air conditioning or refrigeration system is
not performing as designed, a technician is called to the site for trouble shooting
the problem. The technician performs a series of checks that assists in isolating
the problem with the system. One of the causes of the system's problem could
be the compressor used in the system. A faulty compressor exhibits some
operational patterns that could be used to detect the fact that the compressor is
faulty. Unfortunately, many other causes for system problems can be attributed
to other components in the system and these other causes can also affect the
performance of the compressor and its operational pattern. It is possible to
analyze the system's problems and operational patterns and determine that the
compressor is faulty when in fact the problem lies elsewhere and the compressor
is not the problem. This confusion of causes usually results in the replacement
of a good compressor. This error in diagnosis is costly since the compressor is
generally the most expensive component in the system. Further aggravating the
problem is that the root cause for the system's problem has not solved and the
problem recurs in time. Any tool which can help avoid the misdiagnosing of the
system's problem as described above would prove both useful and cost effective.

The present invention discloses a device that increases the accuracy of the
problem diagnosis for an air conditioning or refrigeration system.
[0005] A large part of the compressors used in air conditioning and
refrigeration systems have built-in protection devices called "internal line break
protectors". These protectors are thermally sensitive devices which are wired in
electrical series with the motor. The protectors react thermally to the line current
drawn by the motor and also other temperatures within the compressor including
but not limited to discharge gas temperature, suction gas temperature or
temperature of a particular component in the compressor. When one of these
temperatures exceeds a designed threshold, the protector will open the electrical
connection to the motor. This shuts down the motor operating the compressor
which in turn shuts down the compressor and prevents it from operating in
regions that would lead to its failure. After a period of time, when the
temperatures have fallen to safe levels, the protector automatically resets itself
and the compressor operates again. The temperatures that the protector is
reacting to are a result of the operation of the compressor and the entire system.
Either the operation of the compressor or the operation of the entire system can
influence the temperatures sensed by these protectors. The significant aspect of
the protection system is that some categories of faults repeatedly trip the
protector with very short compressor ON time and other categories of faults trip
the protector less frequently thus providing relatively longer compressor ON
times. For example, a compressor with seized bearings would trip the protector
within about ten seconds of ON time. On the other hand, a system that has a

very low refrigerant charge will trip the protector after tens of minutes of ON time.
An analysis of the trip frequency, trip reset times and compressor ON times will
provide valuable clues in identifying the cause of the system's problems.
[0006] The present invention provides a device which is based on this
principle. The device of the present invention continuously records the status of
the protector (open or closed) as a function of time and then it analyzes this
status information to determine a faulty situation. The device goes further and
isolates the fault to either the compressor or to the rest of the system. Once the
fault has been isolated, the device will activate a visual indicator (light) and it will
also send an electrical signal to any intelligent device (controller, computer, etc.)
advising about the situation. The technician, on arriving at the scene, then has a
clear indication that the problem is most likely in the system components other
than the compressor or the problem is most likely in the compressor. He can
then focus his further trouble shooting to the identified area. The device thus
avoids the previously described situation of a confused diagnosis and the
potential of mistakenly replacing a good compressor.
[0007] Further areas of applicability of the present invention will
become apparent from the detailed description provided hereinafter. It should be
understood that the detailed description and specific examples, while indicating
the preferred embodiment of the invention, are intended for Durposes of
illustration only and are not intended to limited the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention will become more fully understood from
the detailed description and the accompanying drawings, wherein:
[0009] Figure 1 is a vertical cross section of a hermetic scroll
compressor incorporating the unique compressor diagnostic system in
accordance with the present invention;
[0010] Figure 2 is a schematic representation of the diagnostic system
for a single phase motor for the compressor in accordance with the present
invention;
[0011] Figure 3 is a schematic representation of a diagnostic system
for a three phase motor for the compressor in accordance with another
embodiment of the present invention;
[0012] Figure 4 is a flow diagram of the diagnostic system for the single
phase motor for the compressor in accordance with the present invention;
[0013] Figure 5 is a flow diagram of the diagnostic system for the three
phase motor for the compressor in accordance with the present invention;
[0014] Figure 6 is a flow diagram which is followed when diagnosing a
compressor system;
[0015] Figure 7 is a schematic view of a typical refrigeration system
utilizing the compressor and diagnostic system in accordance with the present
invention;

[0016] Figure 8 is a perspective view of a contactor integrated with the
diagnostic system's circuitry in accordance with another embodiment of the
present invention;
[0017] Figure 9 is a schematic view illustrating the circuitry of the
contactor illustrated in Figure 8; and
[0018] Figure 10 is a schematic view of a compressor plug which
illustrates the diagnostic system's circuitry in accordance with another
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The following description of the preferred embodiment(s) is
merely exemplary in nature and is in no way intended to limit the invention, its
application, or uses.
[0020] Referring now to the drawings in which like reference numerals
designate like or corresponding parts throughout the several views, there is
shown in Figure 1 a scroll compressor incorporating the unique compressor
diagnostic system in accordance with the present invention and which is
designated generally by the reference numeral 10. While compressor 10 is being
illustrated as a scroll compressor in conjunction with a refrigeration or air
conditioning system, it is within the scope of the present invention to utilize other
types of compressors in the refrigeration or air conditioning system if desired as
well as having any of the compressor designs being in conjunction with other
types of systems.

[0021] Scroll compressor 10 comprises a generally cylindrical hermetic
shell 12 having welded at the upper end thereof a cap 14 and at the lower end
thereof a base 16 having a plurality of mounting feet (not shown) integrally
formed therewith. Cap 14 is provided with a refrigerant discharge fitting 18 which
may have the usual discharge valve therein. A transversely extending partition
20 is affixed to shell 12 by being welded about is periphery at the same point that
cap 14 is welded to shell 12. A compressor mounting frame 22 is press fit within
shell 12 and it is supported by the end of base 16. Base 16 is slightly smaller in
diameter than shell 12 such that base 16 is received within shell 12 and welded
about its periphery as shown in Figure 1.
[0022] Major elements of compressor 10 that are affixed to frame 22
include a two-piece main bearing housing assembly 24, a lower bearing housing
26 and a motor stator 28. A drive shaft or crankshaft 30 having an eccentric
crank pin 32 at the upper end thereof is rotatably journaled in a bearing 34
secured within main bearing housing assembly 24 and a second bearing 36
secured within lower bearing housing 26. Crankshaft 30 has at the lower end
thereof a relatively large diameter concentric bore 38 which communicates with a
radially outwardly positioned smaller diameter bore 40 extending upwardly
therefrom to the top of crankshaft 30. The lower portion of the interior of shell 12
defines an oil sump 44 which is filled with lubricating oil to a level slightly above
the lower end of a rotor, and bore 38 acts as a pump to pump lubricating fluid up
crankshaft 30 and into bore 40 and ultimately to all of the various portions of
compressor 10 which require lubrication.

[0023] Crankshaft 30 is rotatably driven by an electric motor which
includes stator 28, windings 46 passing therethrough and a rotor 48 press fitted
into crankshaft 30. An upper counterweight 50 is secured to crankshaft 30 and a
lower counterweight 52 is secured to rotor 48. A temperature protector 54, of the
usual type, is provided in close proximity to motor windings 46. Thermal
protector 54 will de-energize the motor if thermal protector 54 exceeds its normal
temperature range. Thermal protector 54 can be heated by motor windings 46,
suction gas within a suction chamber 56 and/or discharge gas within a discharge
chamber 58 which is released into suction chamber 56. Both suction chamber
56 and discharge chamber 58 are defined by shell 12, cap 14, base 16 and
partition 22 as shown in Figure 1.
[0024] The upper surface of two-piece main bearing housing assembly
24 is provided with a flat thrust bearing surface on which is disposed an orbiting
scroll member 60 having the usual spiral vane or wrap 62 extending upward from
an end plate 64. Projecting downwardly from the lower surface of end plate 64 of
orbiting scroll member 60 is a cylindrical hub 66 having a journal bearing therein
and which is rotatably disposed a drive bushing 68 having an inner bore in which
crank pin 32 is drivingly disposed. Crank pin 32 has a flat on one surface which
drivingly engages a flat surface formed in a portion of the inner bore of drive
bushing 68 to provide a radially compliant driving arrangement, such as shown in
Assignee's U.S. Letters Patent 4.877.382, the disclosure of which is hereby
incorporated herein by reference. An Oldham coupling 70 is also provided
positioned between orbiting scroll member 60 and two-piece bearing housing

assembly 24. Oldham coupling 70 is keyed to orbiting scroll member 60 and to a
non-orbiting scroll member 72 to prevent rotational movement of orbiting scroll
member 60.
[0025] Non-orbiting scroll member 72 is also provided with a wrap 74
extending downwardly from an end plate 76 which is positioned in meshing
engagement with wrap 62 of orbiting scroll member 60. Non-orbiting scroll
member 72 has a centrally disposed discharge passage 78 which communicates
with an upwardly open recess 80 which is in turn in communication with
discharge chamber 58. An annular recess 82 is also formed in non-orbiting scroll
member 72 within which is disposed a floating seal assembly 84.
[0026] Recesses 80 and 82 and floating seal assembly 84 cooperate to
define axial pressure biasing chambers which receive pressurized fluid being
compressed by wraps 62 and 74 so as to exert an axial biasing force on non-
orbiting scroll member 72 to thereby urge the tips of respective wraps 62 and 74
into sealing engagement with the opposed end surfaces of end plates 76 and 64,
respectively. Floating seal assembly is preferably of the type described in
greater detail in Assignee's U.S. Letters Patent 5,156,639, the disclosure of
which is hereby incorporated herein by reference. Non-orbiting scroll member 72
is designed to be mounted for limited axial movement with respect to two-piece
main bearing housing assembly 24 in a suitable manner such as disclosed in the
aforementioned U.S. Letters Patent 4,877,382 or Assignee's U.S. Letters Patent
5,102,316, the disclosure of which is hereby incorporated herein by reference.

[0027] Compressor 10 is powered by electricity which is provided to the
electric motor within shell 12 through a molded electric plug 90.
[0028] Referring now to Figures 1 through 3, the present invention is
directed to a unique compressor diagnostic system 100. Diagnostic system 100
comprises one or more current sensing devices 102 and the associated logic
circuitry 104. Current sensing devices 102 are mounted in a housing 106
mounted externally to shell 12. Logic circuitry 104 can be mounted in housing
106 or it can be located in a convenient position with respect to compressor 10
as shown in phantom in Figure 2. Optionally, the sensing device and circuitry
can be integrated into a special contactor, a special wiring harness or into a
molded plug utilized for some compressor designs.
[0029] Current sensing devices 102 sense the current in the power
supply wires powering compressor 10. Figure 2 illustrates two current sensing
devices 102 in conjunction with a single-phase motor. One of the current
sensing devices 102 is associated with the main windings for the compressor
motor and the other current sensing device 102 is associated with the auxiliary
windings for the compressor motor. Figure 3 also illustrates two current sensing
devices 102 in conjunction with a three phase motor. Each current sensing
device 102 is associated with one of the phases of the three phase power supply.
While Figure 3 illustrates two current sensing devices sensing current in two
phases of the three phase power supply, it is within the scope of the present
invention to include a third current sensor 102 to sense the current in the third
phase of the three phase power supply as shown in phantom in Figure 3 if

desired. These current signals represent an indication of the status of protector
54 (open or closed). While current sensing devices 102 sense the status of
protector 54 utilizing the current in the power supply wires, it is also possible to
sense the status of protector 54 by sensing the presence or absence of voltage
on the motor side of protector 54. The inventors of the present invention
consider this to be a less desirable but effective approach in some cases
because it requires an additional hermetic feed-through pin extending through
shell 12. The signals received from current sensing devices 102 are combined in
logic circuitry 104 with the demand signal for compressor 10. The demand signal
for compressor 10 is acquired by sensing the presence of supply voltage or by
having a system controller (not shown) supply a discrete signal representing the
demand. The demand signal and the signal received by logic circuitry 104 are
processed by logic circuitry 104 to derive the information about the trip frequency
of protector 54 and the average ON time and OFF time of compressor 10. Logic
circuitry 104 analyses the combination of current signals, the demand signal and
the derived protector trip frequencies to determine if a fault condition exists.
Logic circuitry also has the unique capability of identifying a specific cause based
on some faults. This information is provided to the service people using a green
LED light 110 and a yellow LED light 112. Green LED light 110 is utilized to
indicate that there is currently no fault condition and that the system is
functioning normally.
[0030] Yellow LED light 112 is utilized to indicate the presence of a
fault. When yellow LED light 112 is turned ON, green LED light 110 is turned

OFF. Thus, yellow LED light 112 is utilized to visually communicate that there is
a fault as well as indicating the type of fault that is present. This communication
is accomplished by turning yellow LED light 112 ON and then OFF for a specific
duration and sequence to indicate both that there is a fault and to identify what
the fault is. For example, turning light 112 ON for one second and turning it OFF
for nineteen seconds and repeating this sequence every twenty seconds will
create the effect of a blinking light that blinks ON once every twenty seconds.
This sequence corresponds to a type of fault that is coded as a type 1 fault. If
light 112 is blinked ON twice for one second during the twenty second window, it
is an indication that a fault that is coded as a type 2 is present. This sequence
continues to indicate a type 3, a type 4 and so on with the type of fault being
indicated by the number of blinks of light 112. This scheme of the blinking of light
112 for a specific number of times is employed to visually communicate to the
technician the various types of faults detected by logic circuitry 104. While the
present invention utilizes blinking light 112 to convey the fault codes, it is within
the scope of the present invention to utilize a plurality of lights to increase the
effectiveness of conveying a large number of fault codes if desired. In addition,
other methods of providing the default code, including providing a coded voltage
output that can be interfaced with a Digital Volt Meter, can also be employed.
[0031] In addition to visually communicating the specific fault code
using light 112, logic circuitry 104 also outputs a coded sequence of electrical
pulses to other intelligent controllers that may exist in the system. These coded
pulses represent the type of fault that has been detected by diagnostic system

100. The types of faults which can be detected by logic circuitry 104 include, but
are not limited to:
1. Protector has "tripped".
2. The auxiliary winding of a single phase motor has no power or is
open or has a faulty run capacitor.
3. The main winding of a single phase motor has no power or that the
winding is open.
4. The main circuit breaker has contacts that have welded shut.
5. One of the phases in a 3 phase circuit is missing.
6. The phase sequence in a 3 phase system is reversed.
7. The supply voltage is very low.
8. The rotor inside the compressor has seized.
9. The protector is tripping due to system refrigeration circuit
problems.
10. The motor windings are open or the internal line break protector is
faulty.
[0032] As a variation to the above, as shown in Figure 3, diagnostic
system 100 may only send the status of protector 54 to an intelligent device 116.
In this option, the parameters of trip frequencies, ON times and OFF times with
the diagnosis information may be generated at intelligent device 116. Intelligent
device 116 can be a compressor controller associated with compressor 10, it can
be a system controller monitoring a plurality of compressors 10, it can be a
remotely located device or it can be any other device which is selected to monitor
diagnostic system 100 of one or more compressors.
[0033] Figure 4 represents a flow diagram for diagnostic system 100 in
conjunction with a single phase compressor. The demand signal is provided to
logic circuitry 104 from a device or a contactor 120 (Figures 2 and 3) along with

the current signal from sensing devices 102. When the system is initially
powered up, an initializing process is performed at 122 and, if successful, the
system, as shown by arrow 124, goes to a normal OFF condition as shown at
126. When sitting at the normal OFF condition 126, if a demand signal is
provided to the system, the system moves as shown by arrow 128 to a normal
run condition shown at 130. Once the demand has been met, the system returns
to the normal OFF condition 126 as shown by arrow 132.
[0034] While sitting at the normal OFF condition 126, if current in the
main winding or current in the auxiliary winding is detected and there has been
no demand signal, the system moves as shown by arrow 134 to a shorted
contactor condition 136. While indicating the shortened contactor condition 136,
if the demand is signaled, the system moves as shown by arrow 138 to the
normal run condition 130. The normal run condition 130 continues until the
demand has been satisfied where the system moves as shown by arrow 132
back to the normal OFF condition 126 which may again move to the shortened
contactor condition 136 depending on whether or not current is sensed in the
main or auxiliary windings.
[0035] While operating in the normal run condition 130, one of three
paths other than returning to the normal OFF condition 126 can be followed.
First, if the system senses demand and main winding current but does not sense
auxiliary winding current, the system moves as shown by arrow 140 to an open
auxiliary circuit condition 142. From here, the system moves to a protector
tripped condition 144 as shown by arrow 146 when both a main winding current

and an auxiliary winding current are not sensed. Second, if the system senses
demand and auxiliary winding current but does not sense main winding current,
the system moves as shown by arrow 148 to an open main circuit condition 150.
From here, the system moves to the protector tripped condition 144 as shown by
arrow 152 when both a main winding current and an auxiliary winding current are
not sensed. Third, if the system senses demand and does not sense auxiliary
winding current and main winding current, the system moves as shown by arrow
154 to the protector tripped condition 144.
[0036] While operating in the protector tripped condition 144, one of
four paths can be followed. First, if main winding current or auxiliary winding
current is sensed and the demand is satisfied, the system moves as shown by
arrow 160 to the normal run condition 130. Second, with the protector tripped,
and the moving window average of the ON time of the system has been less than
twelve seconds, the system moves as shown by arrow 162 to a multiple short run
condition 164. From the multiple short run condition, the system moves back to
the protector tripped condition 144 as shown by arrow 166. Third, with the
protector tripped, and the moving window average of the ON time of the system
has been greater than fifteen minutes, the system moves as shown by arrow 168
to a multiple long run condition 170. The system moves back to the protector
tripped condition 144 as shown by arrow 172. Fourth, with the protector tripped,
if the tripped time exceeds four hours, the system moves as shown by arrow 174
to a power loss or protector defective condition 176. If, while the system is in the
power loss or protector defective condition 176 and main winding current or

auxiliary winding current is sensed, the system moves back to the protector
tripped condition 144 as shown by arrow 178.
[0037] When the system moves to the various positions shown in
Figure 4, the blinking of light 112 is dictated by the fault condition sensed. In the
preferred embodiment, if a protector tripped condition is sensed at 154 because
demand is present but current is missing, light 112 blinks once. If compressor 10
is seized or there is a low supply voltage problem such as indicated by arrow 162
because the average ON time during the last five trips was less than twelve
seconds, light 112 blinks twice. If the motor windings are open, the protector is
faulty or the contactor is faulty as indicated by arrow 174 because the OFF time
is greater than four hours, light 112 blinks three times. If the auxiliary windings
are open or there is a faulty run capacitor as indicated by arrow 140, light 112
blinks four times. If the main winding is open as indicated by arrow 148, light 112
blinks five times. If the contactor is welded as indicated by arrow 134 because
current is sensed but there is no demand, light 112 blinks six times. Finally, if
there are repeated protector trips due to other system problems as indicated by
arrow 168 because the average ON time during the last five trips was less than
fifteen minutes, light 112 blinks seven times.
[0038] Figure 5 represents a flow diagram for diagnostic system 100 in
conjunction with a three phase compressor. The demand signal is provided to
logic circuitry 104 from contactor 120 (Figures 2 and 3) along with the current
signal from sensing devices 102. When the system is initially powered up, an
initializing process is performed at 122 and, if successful, the system, as shown

by arrow 124, goes to a normal OFF condition as shown at 126. When sitting at
the normal OFF condition 126, if a demand signal is provided to the system, the
system moves as shown by arrow 128 to a normal run condition shown at 130.
Once the demand has been met, the system returns to the normal OFF condition
126 as shown by arrow 132.
[0039] While sitting at the normal OFF condition 126, if current in one
of the three phases or current in a second of the three phases is detected and
there has been no demand signal the system moves as shown by arrow 234 to a
shorted contactor condition 136. While indicating the shortened contactor
condition 136, if the demand is signaled, the system moves as shown by arrow
238 to the normal run condition 130. The normal run condition 130 continues
until the demand has been satisfied where the system moves as shown by arrow
132 back to the normal OFF condition 126 which may again move to the
shortened contactor condition 136 depending on whether or not current is sensed
in the main or auxiliary windings.
[0040] While operating in the normal run condition 130, one of three
paths other than returning to the normal OFF condition 126 can be followed.
First, if the system senses demand and eleven milliseconds is less than the zero
crossing time difference between the first and second phases of the three phase
power supply or this time difference is less than fourteen milliseconds, the
system moves as shown by arrow 240 to a phase sequence reversed condition
242. From here, the system moves to a protector tripped condition 144 as shown
by arrow 246 when both a first phase current or a second phase current is not

sensed. Second, if the system senses demand and sixteen milliseconds is less
than the zero crossing time difference between the first and second phases or
this time difference is less than twenty-one milliseconds, the system moves as
shown by arrow 248 to a phase missing condition 250. From here, the system
moves to the protector tripped condition 144 as shown by arrow 252 when both a
first phase current and a second phase current are not sensed. Third, if the
system senses demand and does not sense first phase current and second
phase current, the system moves as shown by arrow 254 to the protector tripped
condition 144.
[0041] While operating in the protector tripped condition 144, one of
four paths can be followed. First, if first phase current or second phase current is
sensed and the demand is satisfied, the system moves as shown by arrow 260 to
the normal run condition 130. Second, with the protector tripped, and the moving
window average of the ON time of the system has been less than twelve
seconds, the system moves as shown by arrow 162 to a multiple short run
condition 164. From the multiple short run condition, the system moves back to
the protector tripped condition 144 as shown by arrow 166. Third, with the
protector tripped, and the moving window average of the ON time of the system
has been greater than fifteen minutes, the system moves as shown by arrow 168
to a multiple long run condition 170. The system moves back to the protector
tripped condition 144 as shown by arrow 172. Fourth, with the protector tripped,
if the tripped time exceeds four hours, the system moves as shown by arrow 174
to a power loss or protector defective condition 176. If, while the system is in the

power loss or protector defective condition 176 and first phase current or second
phase current is sensed, the system moves back to the protector tripped
condition 144 as shown by arrow 278.
[0042] When the system moves to the various positions shown in
Figure 5, the blinking of light 112 is dictated by the fault condition sensed. In the
preferred embodiment, if a protector tripped condition is sensed at 254 because
demand is present but current is missing, light 112 blinks once. If compressor 10
is seized or there is a low supply voltage problem such as indicated by arrow 162
because the average ON time during the last five trips was less than twelve
seconds, light 112 blinks twice. If the motor windings are open, the protector is
faulty or the contactor is faulty as indicated by arrow 174 because the OFF time
is greater than four hours, light 112 blinks three times. If the contactor is welded
as indicated by arrow 234 because current is sensed but there is no demand,
light 112 blinks four times. If there are repeated protector trips due to other
system problems as indicated by arrow 168 because the average ON time during
the last five trips was less than fifteen minutes, light 112 blinks five times. If the
power supply phases are reversed as indicated by arrow 240 because the zero
crossing time difference is between eleven and fourteen milliseconds, light 112
blinks six times. Finally, if there is a phase missing in the three phase power
supply as indicated by arrow 248 because the zero crossing time difference is
between sixteen and twenty-one milliseconds, light 112 blinks seven times.
[0043] While the above technique has been described as monitoring
the moving window averages for compressor 10, it is within the scope of the

present invention to have logic circuitry 104 utilize a real time or the
instantaneous conditions for compressor 10. For instance, in looking at arrows
162 or 168, rather than looking at the moving window average, logic circuitry 104
could look at the previous run time for compressor 10.
[0044] Figure 6 represents a flow diagram which is followed when
diagnosing a system problem. At step 300, the technician determines if there is
a problem by checking the LEDs at step 302. If green LED 110 is lit, the
indication at 304 is that compressor 10 is functioning normally and the problem is :
with other components. If yellow LED light 112 is blinking, the technician counts
the number of blinks at 306. Based upon the number of blinks of light 112 the
determination of the failure type is made at 308. The fault is corrected and the
system is recycled and started at 310. The system returns to step 300 which
again will indicate any faults with compressor 10.
[0045] Thus, diagnostic system 100 provides the technician who
arrives at the scene with a clear indication of most likely where the problem with
the system is present. The technician can then direct his attention to the most
likely cause of the problem and possibly avoid the replacement of a good
compressor.
[0046] Figure 7 illustrates a typical refrigeration system 320.
Refrigeration system 320 includes compressor 10 in communication with a
condensor 322 which is in communication with an expansion device 324 which is
in communication with an evaporator 326 which is in communication with

compressor 10. Refrigerant tubing 328 connects the various components as
shown in Figure 7.
[0047] Referring now to Figure 8, a contactor 120 is illustrated which
incorporates diagnostic system 100 in the form of current sensors 102, logic
circuitry 104, green LED light 110 and yellow light 112. Contactor 120.is
designed to receive information from various system controls such as a system
thermostat 350 (Figures 2 and 3), a group of system safeties 352 (Figures 2 and
3) and/or other sensors incorporated into the system and based upon three
inputs provide power to compressor 10.
[0048] Contactor 120 includes a set of power-in connectors 354, a set
of power-out connectors 356, a set of contactor coil connectors 358, light 110
and light 112. The internal schematic for contactor 120 is shown in Figure 9. A
power supply 360 receives power from connectors 354, converts the input power
as needed and then supplies the required power to input circuitry 362,
processing circuitry 364 and output circuitry 366, which collectively form logic
circuitry 104.
[0049] Input circuitry 362 receives the input from current sensors 102
and the demand signal in order to diagnose the health of compressor 10. The
information received by input circuitry 362 is directed to processing circuitry 364
which analyses the information provided and then provides information to output
circuitry 366 to operate compressor 10 and/or activate LED lights 110 and 112.
The incorporation of logic circuitry 104 into contactor 120 simplifies the system
due to the fact that both the line power and the demand signal are already

provided to contactor 120. The function and operation of diagnostic system 100
incorporated into contactor 120 is the same as described above for housing 106.
[0050] Referring now to Figure 10, molded plug 90 is illustrated
incorporating diagnostic system 100 in the form of current sensors 102, logic
circuitry 104, light 110 and light 112. In some applications, incorporation of
diagnostic system 100 into molded plug 90 offers some distinct advantages.
When diagnostic system 100 is incorporated into molded plug 90, power is
provided through connectors 354 and must also be provided to diagnostic system
from the input power or it can be provided separately through connector 370. In
addition, the demand signal must also be provided to plug 90 and this can be
done through connectors 372. The function and operation of diagnostic system
100 incorporated into molded plug 90 is the same as described above for
housing 106. Communication from plug 90 is accomplished through connection
374.
[0051] The description of the invention is merely exemplary in nature
and, thus, variations that do not depart from the gist of the invention are intended
to be within the scope of the invention. Such variations are not to be regarded as
a departure from the spirit and scope of the invention.

We Claim:
1. A compressor assembly comprising:
a compressor;
an electric motor attached to said compressor for powering said
compressor;
a thermal protector associated with said motor, said motor
protector actuatable between a first portion when said motor is
within specified operating parameters, and a second position when
said motor is outside of said specified operating parameters; and
characterized in that:
a compressor diagnostic system associated with said motor
protector, said diagnostic system being able to diagnose a
compressor assembly problem based upon the status of said motor
protector.
2. The compressor assembly as claimed in claim 1, wherein said
diagnostic system includes an indicator which shows the status of
said motor protector.
3. The compressor assembly as claimed in claim 2, wherein said
diagnostic system includes an indicator which identifies a specific
problem.
4. The compressor assembly as claimed in claim 1, wherein said

diagnostic system includes an indicator which shows a system
problem.
5. The compressor assembly as claimed in claim 1, wherein said
diagnostic system monitors when said compressor is operating and
when said compressor is idle.
6. The compressor assembly as claimed in claim 5, wherein said
diagnostic system monitors the length of time said motor protector
stays in said second position.
7. The compressor assembly as claimed in claim 1, wherein said
diagnostic system monitors the length of time said motor protector
stays in said second position.
8. The compressor assembly as claimed in claim 1, wherein at least
one current sensor is provided for determining said status of said
motor protector.
9. The compressor assembly as claimed in claim 8, wherein a demand
signal is provided, said demand signal in conjunction with said
status of said motor protector being used to diagnose said
compressor problem.

10. The compressor assembly as claimed in claim 1, wherein a demand
signal is provided, said demand signal in conjunction with said
status of said protector being used to diagnose said compressor
problem.
11. The compressor assembly as claimed in claim 1, wherein an
electric plug is provided, said diagnostic system being integrated
into said electrical plug.
12. The compressor assembly as claimed in claim 1, wherein a
contactor is provided, said diagnostic system being integrated into
said contactor.
13. A cooling system comprising:
a condensor;
an expansion device in communication with said condensor; and
a compressor assembly as claimed in the preceding claims.
14. The compressor assembly as claimed in claim 13, wherein at least
one current sensor is provided for determining said status of said
motor protector.
15. The compressor assembly as claimed in claim 14, wherein a
demand signal is provided, said demand signal in conjunction will

said status of said motor protector being used to diagnose said
compressor problem.
16. The compressor assembly as claimed in claim 13, wherein a
demand signal is provided, said demand signal in conjunction with
said status of said motor protector being used to diagnose said
compressor problem.
17. The compressor assembly as claimed in claim 13, wherein an
electrical plug is provided, said diagnostic system being integrated
into said electrical plug.
18. The compressor assembly as claimed in claim 13, wherein a
contactor is provided, said diagnostic system being integrated into
said contactor.
19. The compressor assembly as claimed in claim 13, wherein a
thermal motor protector is provided, said electric circuitry being
able to sense a status of said motor protector.
20. The compressor assembly as claimed in claim 19, wherein said
electronic circuitry includes at least one current sensor.
21. The compressor assembly as claimed in claim 13, wherein said
electronic circuitry includes at least one current sensor.

22. The compressor assembly as claimed in claim 13, wherein said
electronic circuitry comprises a compressor diagnostic system able
to diagnose a problem with said compressor assembly.
Dated this 18th day of March 2002.

A compressor assembly comprising: a compressor; an electric motor
attached to said compressor for powering said compressor; a thermal
protector associated with said motor, said motor protector actuatable
between a first portion when said motor is within specified operating
parameters, and a second position when said motor is outside of said
specified operating parameters; and characterized in that:
a compressor diagnostic system associated with said motor protector, said
diagnostic system being able to diagnose a compressor assembly problem
based upon the status of said motor protector.

Documents:

149-CAL-2002-FORM-27.pdf

149-cal-2002-granted-abstract.pdf

149-cal-2002-granted-assignment.pdf

149-cal-2002-granted-claims.pdf

149-cal-2002-granted-correspondence.pdf

149-cal-2002-granted-description (complete).pdf

149-cal-2002-granted-drawings.pdf

149-cal-2002-granted-examination report.pdf

149-cal-2002-granted-form 1.pdf

149-cal-2002-granted-form 13.pdf

149-cal-2002-granted-form 18.pdf

149-cal-2002-granted-form 2.pdf

149-cal-2002-granted-form 26.pdf

149-cal-2002-granted-form 3.pdf

149-cal-2002-granted-form 5.pdf

149-cal-2002-granted-form 6.pdf

149-cal-2002-granted-gpa.pdf

149-cal-2002-granted-reply to examination report.pdf

149-cal-2002-granted-specification.pdf

149-cal-2002-granted-translated copy of priority document.pdf

« Previous Patent

Next Patent »

Patent Number

230345

Indian Patent Application Number

149/CAL/2002

PG Journal Number

09/2009

Publication Date

27-Feb-2009

Grant Date

25-Feb-2009

Date of Filing

18-Mar-2002

Name of Patentee

COPELAND CORPORATION

Applicant Address

1675 W. CAMPBELL ROAD, SIDNEY OHIO 45365-0669

Inventors:

#	Inventor's Name	Inventor's Address
1	JAYANTH NAGARAJ	1256 E, PARKWOOD STREET, SIDNEY OHIO 45365
2	MILLET, HANK E	8655 N.UNION SHELBY ROAD, PIQUA, OHIO 45356

PCT International Classification Number

F25B 49/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	09/818,271	2001-03-27	U.S.A.