Title of Invention

"MICRO-CONTROLLER BASED CIRCUIT BREAKER HAVING VARIABLE CURRENT RATING"

Abstract A micro-controller based Circuit Breaker having variable current rating for use in low voltage electrical distribution systems, said MCCB comprising one or more Current Sensors (C.S) (1) for sensing and measuring the current flowing through the circuit breaker a micro-controller (2)connected to said current sensors for receiving its output, comparing it with a user defined value and outputting a tripping signal based on the comparison to a tripping mechanism (3) which in turn, trips the circuit breaker, and optionally comprising a temperature sensor (4) a display device (7) an external memory (5) and one or more DIP switches (6).
Full Text MICRO CONTROLLER BASED MOLDED CASE CIRCUIT BREAKER
FIELD OF THE INVENTION
The present invention relates to a novel Micro-controller based Molded Case Circuit Breaker (MCCB) having variable current rating used for the protection of low voltage electrical distribution systems.
BACKGROUND OF THE INVENTION
The Molded Case Circuit Breakers (MCCBs) fill in the void between conventional Miniature Circuit Breakers (MCBs) which are limited by IS to 63A and Air Circuit Breakers (ACBs) which are generally over 1000A. Over the years, there has been considerable overlapping due to the advancements in technologies in the role of MCCBs and ACBs in the protective systems.
The MCCBs are extensively used in low voltage domestic, commercial and industrial applications. They replace conventional fuses and combine the features of a good High Rupturing Capacity (HRC) fuse and a good switch. For normal operation, it is used as a switch. During overload or faults, it automatically trips off. Magnetic and thermal sensing devices provided within the MCCB actuate the tripping mechanism.
Tripping mechanism and thermal contacts are assembled in a molded case, molded out of thermosetting powders. This ensures high mechanical strength, high dielectric strength and virtually no ageing. The current carrying parts are made out of electrolytic copper or silver alloy, depending upon the rating of the breaker. All other metal parts are made out of non-ferrous, non-rusting type metals. The arc chute present in the MCCB has a special construction, which increases the length of the arc by magnetic field created by the arc itself, and the arc chute is so placed in the breaker that the hot gases may not come in contact with any important parts of the breaker.
The increased growth of power systems in both size and complexity has brought about the need for fast and reliable MCCBs to protect major equipment and to maintain stability. The conventional protective schemes are either of electromagnetic or static type. The electromagnetic protective schemes have several drawbacks such as high burden on
instrument transformers, high operating time, contact problems, etc. Static schemes have been increasingly used in recent years because of their inherent advantages of compactness, low burden, less maintenance, and high speed. Though successfully used, they suffer from a number of disadvantages, e.g. inflexibility, inadaptability to changing system conditions and complexity.
Traditional MCCBs do not allow the user to change their current ratings. As an example we will consider the following hypothetical scenario. A workshop buys a new motor having a current rating of 25 amperes. The workshop in-charge now buys a breaker having a current rating of 30 amperes, as breakers of 25 amps rating were not available at the time he went to make the purchase. The problem that the workshop now faces is that the two devices are totally incompatible. The reason for their incompatibility being that for the motor any current greater than 25A constitutes an overload whereas, currents greater than 30A are overload for the breaker. Hence, in the overload range of 25 to 30A, the breaker does not provide the motor with any overload protection.
This hypothetical scenario is becoming a reality in many industries where the use of special machines warrants the use of breakers having non-standard current ratings. MCCBs with non-standard current ratings are not manufactured, due to practical problems in manufacturing these ratings economically.
The concept of digital protection employing computers which shows much promise in providing improved performance has evolved during the past two decades. Computer hardware technology has tremendously advanced since early 1970s and a new generation of computers tends to make digital protection a viable alternative to the traditional protective systems. The advent of micro-controllers in the 1970s initiated a revolution in design and development of digital protection schemes. With the development of economical, powerful and sophisticated micro-processors, there is a growing interest in developing micro-controller based protection which are more flexible because of being programmable and are superior to conventional electromagnetic and static protection.
In the present case, the Applicant has developed a micro-controller based MCCB whose current rating can be varied over a wide range by simply changing data in the program. This micro-controller based MCCB provides the user to modify its nominal current rating. Due to this, the standard breaker may be used for any application by changing the values stored in the micro-controller. This however is subject to the condition that the machines operating limits are not exceeded.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide a micro-controller based Molded Case Circuit Breaker (MCCB) used for the protection of low voltage electrical distribution systems and whose current rating can be varied over wide range.
SUMMARY OF THE INVENTION
The present invention relates to a micro-controller based Moulded Case Circuit Breaker (MCCB) having variable current rating for use in low voltage electrical distribution systems, said MCCB comprising one or more Current Sensors (C.S) for sensing and measuring the current flowing through the MCCB; a micro-controller connected to said current sensors for receiving its output, comparing it with a user defined value and outputting a tripping signal based on the comparison to a tripping mechanism which in turn, trips the MCCB and optionally comprising a temperature sensor, a display device, an external memory and one or more DIP switches.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the present invention provides a micro-controller based Moulded Case Circuit Breaker (MCCB) having variable current rating for use in low voltage electrical distribution systems, said MCCB comprising one or more Current Sensors (C.S) for sensing and measuring the current flowing through the MCCB; a micro-controller connected to said current sensors for receiving its output, comparing it with a user defined value and outputting a tripping signal based on the comparison to a tripping mechanism which in turn, trips the MCCB, and optionally comprising a temperature sensor, a display device, an external memory and one or more DIP switches.
In an embodiment of the present invention, there are provided three current sensors, one for each phase in the MCCB.
In another embodiment of the present invention, the current sensor comprises of a 'U' shaped electromagnet and a Hall Effect 1C.
In still another embodiment of the present invention, the Hall Effect 1C incorporates a Hall Effect transducer and an operational amplifier.
In yet another embodiment of the present invention, the 'U' shaped electromagnet produces a magnetic field whose intensity depends upon the current flowing through the MCCB.
In one more embodiment of the present invention, the Hall Effect 1C is located at a predetermined distance from the 'U' shaped electromagnet for measuring the current flow.
In one another embodiment of the present invention, the Hall Effect 1C is located such that the magnetic field produced by the 'U' shaped electromagnet is linked to the Hall Effect 1C.
In an embodiment of the present invention, the Hall Effect 1C is located such that the 'U' shaped electromagnet induces a voltage, proportional to the magnetic field, in the Hall Effect transducer.
In another embodiment of the present invention, the operational amplifier inside the Hall Effect transducer amplifies the Hall Effect voltage.
In still another embodiment of the present invention, the Hall Effect 1C is of linear type giving a differential output.
In yet another embodiment of the present invention, the Hall Effect 1C operates on a standard 5V reference supply.
In one more embodiment of the present invention, the micro-controller is INTEL N8 x C196MDorabove.
In one another embodiment of the present invention, the micro-controller has an operating speed of 20 MHz and above.
In an embodiment of the present invention, the output of the Hall Effect 1C is given to an A/D pin of the micro-controller having an in-built A/D converter.
In another embodiment of the present invention, the output of the A/D converter is given to an in-built multiplexer.
In still another embodiment of the present invention, there are provided two DIP switches for inputting rated current (!R) and maximum threshold current (!M).
In yet another embodiment of the present invention, the value of IR can be set up to the rated nominal current of the MCCB.
In one more embodiment of the present invention, the value of IM is set as a multiple of IR.
In one another embodiment of the present invention, the DIP switches are connected to the Input / Output (I/O) ports of the micro-controller.
In an embodiment of the present invention, the DIP switches are read and the data read are placed into appropriate registers during the boot-up sequence.
In another embodiment of the present invention, as a precautionary step, the IR and IM values once selected can be modified only by rebooting/resetting the micro-controller.
In still another embodiment of the present invention, the actual values of IM are stored in a look-up table in the memory and the data read in from the DIP switch corresponding to IM serves only as a pointer.
In yet another embodiment of the present invention, the values of IR and IM are fed in binary form.
In one more embodiment of the present invention, the tripping mechanism consists of a plunger and a Buffer (latch).
In one another embodiment of the present invention, the Buffer latches the trip signal given by the micro-controller and supplies the current required to drive the plunger and also outputs a signal to display "TRIP" on the display device till the device is reset.
In an embodiment of the present invention, the plunger trips the MCCB.
In another embodiment of the present invention, the output of the temperature sensor is given to an A/D pin of the micro-controller to numerically compensate for the thermal drift of the Hall Effect Transducer.
In still another embodiment of the present invention, the display device is a Liquid Crystal Display (LCD).
In yet another embodiment of the present invention, the LCD is connected to any one of the six I/O ports of the micro-controller.
In one more embodiment of the present invention, the LCD gives indication of the chosen rating of the MCCB and on tripping, indicates the current at which the MCCB tripped.
In one another embodiment of the present invention, an external memory is provided to the micro-controller if it as no memory.
In an embodiment of the present invention, the external memory stores the program and other data.
In another embodiment of the present invention, the micro-controller is provided with 32 KB of external memory.
In still another embodiment of the present invention, the external memory provided is in the form of 2 x 16K EPROM's.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
In the drawings accompanying the specification, Figure 1 represents a block diagram of micro-controller based MCCB. Figure 2 represents the current conductor assembly (current sensor) of the MCCB. Figure 3 represents the INTEL chip components on the PV board present in the microcontroller. Figure 4 represents the I-t curve for the MCCB.
The present invention is further described with respect of the preferred embodiments which are given by way of illustration and therefore, should not be construed to limit the scope of the present invention in any manner.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to figure 1, the micro-controller based MCCB of the present invention provides protection for short circuit, overload for various other load protections. In the present invention, the Applicants have used a breaker of nominal current rating of 250A. The MCCB consists of current sensors which sense the current flowing through the MCCB at the input terminals. The current sensor is a very essential part of the microcontroller based MCCB as it senses and gives an equivalent output voltage to the microcontroller. The MCCB uses three current sensors (CS1, CS2 and CSS), one for each phase so that it can sense fault on any of the phases. The current sensor is a novel component especially constructed for the present invention. The censor has U-shaped electromagnet which gets magnetized when current is passed through it. The Applicants in the present invention have used Hall Effect Transducer/ Hall Effect Chip (HE Chip) which gives a differential output. The HE chip is located at a predetermined distance for measuring the current flow based on the magnetic field created by the U-shaped electromagnet. Figure 2 (a) shows the side view of the current censor wherein the U-shaped electromagnet and the HE chip are clearly shown. Figure 2 (b) shows the top view of the current censor.
The choice of the current censor was limited to two options:
1. Current Transformer and
2. Hall Effect Transducer (HE Chip)
Trials with self fabricated type of current transformer proved to be cumbersome as this presented a host of problems as mentioned below:
1. Size constraint: The space available is very small in the range of 1-2 cm2.
As in the present case, three current censors were require, it became nearly
impossible to accommodate three Current Transformers (C.Ts) without modifying
the size and design of the commercially available MCCB.
2. Auxiliary Circuitry Required: The output of the C.Ts is current
while the micro-controller senses a voltage input, hence a current to voltage
converter would have to be connected between the C.T and the micro-controller
for its usage. Further, a rectifier will also have to be used to convert the AC input
into a D.C. output as the micro-controller can accept only D.C. input.
Moreover, the Hall Effect Transducer offers numerous advantages as described below:
1. Small Size: The size of the transducer is 5.3 X 7.5 mm.
2. Isolation: The Hall Effect Transducer is never in contact with any current
carrying part of the MCCB, thus it offers complete electrical isolation.
3. Life Span: Hall Effect transducer has an unlimited life span.
4. Accuracy: The Hall Effect Transducer has a very high accuracy when
compared to the C.T.
The linear Hall Effect chip works on the principle of Hall Effect which can be explained as below:
The basic physical principle underlying the Hall effect is the Lorentz force. When an electron moves along a direction perpendicular to an applied magnetic field, it experiences a force acting normal to both directions and moves in response to this force and the force effected by the internal electric field. The electrons subject to the Lorentz force initially drift away from each thereby resulting in a potential drop. For example, the
Hall effect will occurs when charge carriers moving through a material experience a deflection because of an applied magnetic field. This deflection results in a measurable potential difference across the side of the material which is transverse to the magnetic field and the current direction. If a voltmeter is brought in contact with the material under these conditions, a small, finite quantity of voltage will be detected.
The Hall effect transducer 1C incorporates an operational amplifier that amplifies the potential differences and makes it available at the output pin. In a linear hall effect transducer, the output of operational amplifier is given directly to the output pin, while in a differential type hall effect transducer, output of operational amplifier is compared with a fixed internal voltage and made available at the output pin. The Hall effect transducer operates on a +5V reference supply.
The output of the Hall Effect 1C is given to the A/D pins of the micro-controller. It is observed that the output of the transducer varies with temperature, hence it is necessary to provide adequate temperature compensation as the temperature ithin the MCCB varies over a wide range. For this purpose, the Applicants have used a temperature sensor whose output is given to a fourth A/D pin of the micro-controller.
The micro-controller, which is the heart of the present invention, controls the functions of the MCCB. The micro-controller decides logically the conditions under which the tripping signal is given to the tripping mechanism. The Applicants have used a ROM-less micro-controller, whose output is in-turn given to an in-built multiplexer. The basic algorithm of the working of the microprocessor is given below.
ALGORITHM FOR THE OPERATION OF THE MICRO-CONTROLLER
1. Initialize all variables to zero, read IR and IM from the ports (DIP switches) and
initialize Timer 1 = Timer 2 = Timer 3 = 0.
2. Reset = 1
3. Read temperature value into T.
4. Calculate temperature compensation factor KI for the Hall Effect Transducer.
5. Read value from transducer 1.
6. Multiply the value read from the transducer by scaling coefficient K2 to get true
numerical value of l\. 1. Repeat steps 5 and 6 for Ij and 13 from transducers 2 and 3 respectively.
8. If Reset = 1, then evaluate calculation T states (i.e. wait) for steps 9 through 13
else do step 9.
9. IRMSI =

10. If IRMSI >IM, then go to step 15.
11. If IRMSI > IR then Timer 1 = Timer 1 + t else if IRMSI Timer 1 = Timer 1 - t.
12. If Timer 1 > Thermal then go to step 15.
13. Repeat steps 9 through 12 to check IRMS2 and IRMS3-
14. Set IPREVI = Ii; IpREV2 = t and IPREv3 = Is-
15. Send tripping signal to output port and wait for reset signal.
LIST OF VARIABLE AND CONSTANTS USED IN THE ALGORITHM:
Ii, \2 and la = Latest numerical values of current in all three phases.
IPREVI, IpREV2 and IPREVS = Numerical values of current from the previous loop.
IRMSI , IRMSZ and IRMSS = Latest numerical RMS (root mean square) values of the currents
as calculated from I and IPREV-
Timer 1, Timer 2 and Timer 3 = These act as times to keep touch of the duration that the
currents are in overload (Thermal).
Thermal = The maximum thermal overload time (Fined).
IR = Rated value of current as set by User Interface (DIP Switches).
IM = Maximum value of current as set by the User Interface (DIP Switches).
t = Cycle (loop) time of the algorithm in seconds.
K.2 = Coefficient to extract the true value of current from the output signal value of the transducer.
KI = Hall effect temperature compensation coefficient to compensate for the linear thermal drift of the Hall Effect transducer.
f = supply frequency of the measured current usually it is equal to 50 Hz. This value is fixed in memory of the microprocessor. This value may be changed depending on the Power System frequency or the country.
DETAILED DESCRIPTION OF THE ALGORITHM:
The values of IR and IM are set by the user through the user interface i.e. through the DIP switches. IR and IM values constitute the threshold values of thermal overload current and short circuit current respectively. These values dictate the shape of the I-t curve since, the values of thermal tripping time and short circuit tripping time are fixed.
The temperature sensor provides the actual temperature conditions inside the MCCB to offset the thermal variations of the Hall effect transducer. The temperature variations are numerically compensated according to the characteristic curve of the Hall effect transducer. The Hall effect transducer manufacturer usually gives the temperature compensation factor in the data sheet.
The Root Mean Square values of the currents in all phases are calculated by using the two consecutive sampled values. The timer variables keep track of the thermal overload times of each phase respectively thereby.
Once it is determined that numerical RMS value of the current is greater than maximum rated value of the current set by the user, the micro-controller sends the trip signal to the buffer which latches on this signal and supplies it to the plunger to initiate the tipping action. The buffer also sends a signal to the LCD to display "TRIP".
One of the key features of the present invention is the scalability of the MCCB. The user can select different values of rated current (!R) and maximum threshold current (IM). The selection of these current ratings has been made possible by incorporating two "DIP" switches. In the present invention, the Applicant has provided a "DIP" switch for the IR, using which, the user can change its current rating from 0 to 250A. The advantages of this are obvious. By setting the "DIP" switch for 25A, the same breaker could be used for the 25A motor now. The Applicants have provided a second "DIP" switch for selecting value of IM- However, this switch may be used only for the values as shown on the legend
on the control module. The reason being that wide variations in IM are not required. The Applicants have provided overload-sensing limits of 1.5, 2, 3, 4 and 5 times the value of IR selected.
The selected values of rated current and maximum threshold current are given to two ports of the micro-controller. As the micro-controller of the present invention is ROM-less, i.e. has no memory, external memory should be provided to store the program and other data. Hence, 32 KB of memory is provided in the form of 2X16k EPROM's.
The Applicants have also provided the option of using a Liquid Crystal Display (LCD) which will give the user an indication of the chosen rating of the MCCB and on tripping, indicate the current at which the MCCB tripped. This LCD is connected to one of the six I/O ports available on the micro-controller.
The tripping mechanism consists of a plunger and a buffer (latch). When the microcontroller senses a fault, it gives a trip signal to the plunger, which in turn, trips the MCCB. A buffer is used as the micro-controller is unable to supply current required to drive the plunger.
In the present case, one of the main advantages of using an advanced HMOS technology based micro-controller would be that the proposed system would have the flexibility in both design and operation that would otherwise not be possible in a conventional system. Thus, far better control over the operation of the MCCB is obtained. By changing the values in the program the same MCCB may be used for other applications as well. In fact, the operation of the protective system could, with minor program changes be incorporated to include earth fault protection as well. In a fast changing world of digital electronics, the role played by electronic control devices such as Micro-controller systems cannot be emphasized enough. These systems offer flexible and seamless integration with a very wide range of data acquisition and control systems. Also inter-protective device communication in a protective scheme is very easily implemented by means of serial communication protocols.
With the obvious features offered such as fine tuning of characteristics, a greater degree of control is in the hands of the end user and system designer so that no compromises have to be made (which would have ordinarily been made in case of a conventional device) due to inflexible (or at best marginal degree of flexibility) device behavior.
The very nature of these static devices requires that a high degree of electrical isolation be maintained for the proper operation of the devices in question. Therefore, by the use of advanced hall effect transducers, equipment safety as well as operator safety are not compromised in any way but are enhanced as compared to traditional MCCBs.
ADVANTAGES OF THE PRESENT INVENTION
The micro-controller based MCCBs of the present invention offer the following inherent advantages over conventional electromagnetic MCCBs:
1. The digital protective schemes consume less power as it uses semi-conductor
device and in most of the cases, they draw power from the auxilary D.C. supply.
2. Fast response.
3. Long life.
4. High resistance to shock and vibration.
5. Less maintenance due to absence of moving parts and bearings.
6. Frequent operations cause no deterioration.
7. Quick resetting and absence of overshoot.
8. Compact size.
9. Greater sensitivity as amplification can be provided easily.
10. Complex relaying characteristics can easily be obtained.
11. Logic circuits can be used for complex protective schemes.
12. It is easy to integrate such a piece of equipment into an electronic control system i.e.,
they can become a part of data acquisition system and protection system. Since
data is digitally transferred, it is easy to plug it into a computer for further analysis.
13. It is a very safe and secure system.
14. This system can select multiple ratings, as a result fine tuning of characteristics can
be obtained.
15. Also a very high degree of isolation can be obtained by the use of Hall effect devices.




WE CLAIM:
1. A micro-controller based Moulded Case Circuit Breaker (MCCB) having variable
current rating for use in low voltage electrical distribution systems, said MCCB
comprising one or more Current Sensors (C.S) for sensing and measuring the
current flowing through the MCCB; a micro-controller connected to said current
sensors for receiving its output, comparing it with a user defined value and
outputting a tripping signal based on the comparison to a tripping mechanism
connected to it which in turn, trips the MCCB, and optionally a temperature
sensor, an external memory and one or more DIP switches connected to the input
of the microprocessor and a display device connected to another output of the
microprocessor.
2. A MCCB as claimed in claim 1, wherein there are provided three current sensors,
one for each phase in the MCCB.
3. A MCCB as claimed in claim 1, wherein the current sensor comprises of a 'U'
shaped electromagnet and a Hall Effect IC.
4. A MCCB as claimed in claim 3, wherein the Hall Effect IC incorporates a Hall
Effect transducer and an operational amplifier.
5. A MCCB as claimed in claim 3, wherein the 'U' shaped electromagnet produces a
magnetic field whose intensity depends upon the current flowing through the
MCCB.
6. A MCCB as claimed in claim 3, wherein the Hall Effect IC is located at a
predetermined distance from the 'U' shaped electromagnet for measuring the
current flow.
7. A MCCB as claimed in claim 3, wherein the Hall Effect IC is located such that
the magnetic field produced by the 'U' shaped electromagnet is linked to the Hall
Effect IC.
8. A MCCB as claimed in claim 3, wherein the Hall Effect IC is located such that
the 'U' shaped electromagnet induces a voltage, proportional to the magnetic
field, in the Hall Effect transducer.
9. A MCCB as claimed in claim 4, wherein the operational amplifier inside the Hall
Effect transducer amplifies the Hall Effect voltage.
10. A MCCB as claimed in claim 3, wherein the Hall Effect IC is of linear type
giving a differential output.
11. A MCCB as claimed in claim 3, wherein the Hall Effect IC operates on a standard
5V reference supply.
12. A MCCB as claimed in claim 1, wherein the micro-controller is INTEL N8 x
C196 MD or above.
13. A MCCB as claimed in claim 1, wherein the micro-controller has an operating
speed of 20 MHz and above.
14. A MCCB as claimed in claim 1, wherein the output of the Hall Effect IC is given
to an A/D pin of the micro-controller having an in-built A/D converter.
15. A MCCB as claimed in claim 14, wherein the output of the A/D converter is
given to an in-built multiplexer.
16. A MCCB as claimed in claim 1, wherein there are provided two DIP switches for
inputting rated current (IR) and maximum threshold current (IM).
17. A MCCB as claimed in claim 16, wherein the value of IR can be up to the rated
nominal current of the MCCB.
18. A MCCB as claimed in claim 16, wherein the value of IM is set as a multiple of IR.
19. A MCCB as claimed in claim 16, wherein the DIP switches are connected to the
Input / Output (I/O) ports of the micro-controller.
20. A MCCB as claimed in claim 16, wherein the DIP switches are read and the data
read are placed into appropriate registers during the boot-up sequence.
21. A MCCB as claimed in claim 16, wherein as a precautionary step, the IR and IM
values once selected can be modified only by rebooting/resetting the micro
controller.
22. A MCCB as claimed in claim 16, wherein the actual values of IM are stored in a
look-up table in the memory and the data read in from the DIP switch
corresponding to IM serves only as a pointer.
23. A MCCB as claimed in claim 16, wherein the values of IR and IM are fed in binary
form.
24. A MCCB as claimed in claim 1, wherein the tripping mechanism consists of a
plunger and a Buffer (latch).
25. A MCCB as claimed in claim 24, wherein the Buffer latches the trip signal given
by the micro-controller and supplies the current required to drive the plunger and
also outputs a signal to display "TRIP" on the display device till the device is
reset.
26. A MCCB as claimed in claim 24, wherein the plunger trips the MCCB.
27. A MCCB as claimed in claim 1, wherein the output of the temperature sensor is
given to an A/D pin of the micro-controller to numerically compensate for the
thermal drift of the Hall Effect Transducer.
28. A MCCB as claimed in claim 1, wherein the display device is a Liquid Crystal
Display (LCD).
29. A MCCB as claimed in claim 1, wherein the LCD is connected to any one of the
six I/O ports of the micro-controller.
30. A MCCB as claimed in claim 1, wherein the LCD gives indication of the chosen
rating of the MCCB and on tripping, indicates the current at which the MCCB
tripped.
31. A MCCB as claimed in claim 1, wherein an external memory is provided to the
micro-controller if it as no memory.
32. A MCCB as claimed in claim 31, wherein the external memory stores the
program and other data.
33. A MCCB as claimed in claim 31, wherein the micro-controller is provided with
32 KB of external memory.
34. A MCCB as claimed in claim 31, wherein the external memory provided is in
the form of 2 x 16K EPROM's.
35. A micro-controller based Moulded Case Circuit Breaker (MCCB) having variable
current rating substantially as herein described before with respect to the
examples and the drawings.

Documents:

836-del-2000-abstract.pdf

836-del-2000-claims.pdf

836-del-2000-correspondence-others.pdf

836-del-2000-correspondence-po.pdf

836-del-2000-description (complete).pdf

836-del-2000-drawings.pdf

836-del-2000-form-1.pdf

836-del-2000-form-13.pdf

836-del-2000-form-19.pdf

836-del-2000-form-2.pdf

836-del-2000-form-26.pdf

836-del-2000-form-3.pdf

836-del-2000-form-4.pdf

836-del-2000-form-5.pdf

abstract.jpg


Patent Number 197522
Indian Patent Application Number 836/DEL/2000
PG Journal Number 41/2007
Publication Date 12-Oct-2007
Grant Date 08-Oct-2007
Date of Filing 14-Sep-2000
Name of Patentee VIKRAM RANADE, Indian citizen
Applicant Address 11, ISHWAR NAGAR, MATHURA ROAD, NEW DELHI 110065, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 VIKRAM RANADE 11, ISHWAR NAGAR, MATHURA ROAD, NEW DELHI 110065, INDIA.
PCT International Classification Number H01H 73/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA