|Title of Invention||
AN IMPROVED INDUCTION MOTOR
|Abstract||An improved induction motor. This invention provides to an improved induction motor. This invention particularly relates to a Split Rotor Induction Motor.|
|Full Text||This invention relates to an improved induction motor. This invention particularly relates to a Split Rotor Induction Motor.
Induction motors, veritably the 'workhorse1 of the industry are perhaps the most widely used variety of electric motors and there is hardly any area of industrial activity where induction motors are not called upon for the provision of motive power. The ruggedness of motor construction, low cost, minimum maintenance requirements, low operating costs and high energy effi-ciency are factors that have made the induction motor immensely popular in the industrial sector. Induction motors have additionally made inroads into Traction — a precinct that had earlier been the exclusive dominion of DC motors. With the introduction of the concept of efficient energy conversion and performance in the design and selection of electric motors, induction machines are very likely to score over their counterparts, as these machines are more amenable to the dictates of the concept. In short, barring typical operations where particular special features of particular machines are of consequence, induction machines shall, in every likelihood, emerge as the general purpose substitute.
Induction motors can be divided into two major
types, namely Squirrel Cage Induction Motors (SQIM) and Wound Rotor Induction Motors (WRIM). Application area of SQIMs are, in general, much wider in comparison to the WRIMs on account of the fact that these motors are constructionally more robust and rugged and are easier to maintain, since the necessity of regular brush maintenance (as in the case of WRIMs) are totally obviated.
The presently known motors provide the same load carrying capacity and speed to both the left hand side and the right hand side of the power take off shafts. Thus when utilized for such uses as the powering of a vehicle, either a differential gear train is to be used or two different motors need to be used.
The main- object of the present invention is to provide an improved induction motor which obviates the above noted drawbacks. Another object is to provide a split rotor induction motor.
In the improved induction motor of the present invention, a split rotor replaces the integral rotor of a standard SQIM. The rotor of the motor of the present invention has two identical parts. The length of each rotor segment is marginally less than half the length of the standard rotor. These two rotor segments are coupled through a bearing and both are free to rotate. The
assembly occupies the same position relative to the stator. It is therefore apparent that on energizing the stator from an AC supply, identical forces of induction, generated in reaction to the rotating magnetic field set up in the stator, are experienced in both the rotor segments. If free to rotate, the total assembly rotates exactly in the same manner in which a normal machine is expected to rotate and there exists no relative rotary motion between the two rotor segments. However, on arresting the motion of a particular rotor segment, the other rotor segment continues to rotate with the same speed as before. In effect, then, two distinct speeds are obtained from the two halves of the rotor -- a feature that can be used to advantage in many industrial applications. In essence, the load carrying capacity and speed can be made to differ in the left hand side and right hand side of the power take off shafts of the single motor housing of the Split Rotor Induction Motor. This feature is not available from any SQIM.
In Figure I of the drawing accompanying this specification, an assembly drawing which describes the constructional features of the Split Rotor Induction Motor of the present invention is shown.
S is the housing of the SRIM. A designates the two identical rotors. C and Cl represents the different
support bearings. P1 and p2 are the left hand side PTO ( Power Take Off) shaft and the right hand side PTO shaft respectively. Mechanism ( in the mid region M) i.e. the intermediate shaft I achieves the separation of P1 and P2 when loaded differentially. I is the intermediate shaft supported between the two intermediate bearings at two ends. These two bearing C1 are also the end bearings of the two rotors. When assembled, both the rotors are free to rotate in any direction and at any speed, depending upon the condition of the drive. D, the gap between the rotors are maintained in such a fashion that it is as minimum as possible, and at the same time ensuring that there is no fouling between the two rotor segments.
Accordingly, the present invention provides an improved induction motor characterized in having two power take of shafts ( P1 and P2 ) wherein any one of the said shaft is capable of supplying power when other shaft is fully or partially braked, the said induction motor comprises two identical rotors (A,A) mounted on support bearing (C,C1), the said rotors being separated by minimum gap (d) in such a manner that an intermediate free moving shaft connects the inner end support bearing of both the rotors, (C1) the outer end support bearings ( C,C) being connected to the left hand side power take off shaft (P1) and the right hand side power take off shaft (P2) respectively, the assembly of the two rotors being provided with a conventional stator and housing (S).
As has been mentioned earlier, the Split Rotor Induction Motor (SRIM) enjoys the unique distinction where the free rotation of the two rotor segments can be converted to differential rotary motion from an integral source. It is therefore possible to eliminate the differential that is used in conventional vehicles. Moreover, the necessity of incorporating at an enhanced cost two DC motors for driving the two wheels can easily be obviated through their replacement by a single SRIM. In effect then, not only the encumbrances of frequent maintenance of DC motors and the differential are disposed of, but at the same time the unit cost of an electric vehicle is reduced substantially.
The main advantages of the improved induction motor of the present invention are :
1) A Split Rotor Induction Motor wherein any one of
the two power take off (PTO) shafts are capable of
supplying power (torque and rotation) when the
other PTO shaft is fully or partially braked.
2) A Split Rotor Induction Motor wherein the two
identical PTO shafts of the motor are capable of
supplying power (torque and rotation) different
from each other in magnitude when each one of
these are loaded with different magnitudes (dif
1. An improved induction motor characterized in having two power take of
shafts ( P1 and P2 ) wherein any one of the said shaft is capable of
supplying power when other shaft is fully or partially braked, the said
induction motor comprises two identical rotors (A,A) mounted on support
bearing (C,C1), the said rotors being separated by minimum gap (d) in
such a manner that an intermediate free moving shaft connects the inner
end support bearing of both the rotors , (C1) the outer end support
bearings ( C,C) being connected to the left hand side power take off shaft
(P1) and the right hand side power take off shaft (P2) respectively, the
assembly of the two rotors being provided with a conventional stator and
2. An improved induction motor substantially as herein described with
reference to the drawing accompanying.
|Indian Patent Application Number||254/DEL/1997|
|PG Journal Number||38/2008|
|Date of Filing||31-Jan-1997|
|Name of Patentee||COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH|
|Applicant Address||RAFI MARG, NEW DELHI 110 001,INDIA.|
|PCT International Classification Number||H 02 K 17/12|
|PCT International Application Number||N/A|
|PCT International Filing date|