why the no.of slots in stator in not equal to the no. of
stator in rotor in induction motor????




Answers were Sorted based on User's Feedback



Answer / shankar

Have you ever heard about cogging in induction motors. When the number of stator slots is equal to the number of rotor slots, forces due to reluctance are produced which dominates the accelerating starting torque of induction motor and hence reduces it. So the motor wont rotate when the no of stator slots is equal to number of rotor slots. This phenomenon in induction motor is called Cogging.

This does not occur in slip ring induction motors. you know why?? because of high starting torque.

Is This Answer Correct ?    28 Yes 1 No

Answer / raul

yes the exact term is COGGING....which means if the stator
poles and rotor poles are equal or in integral ratio, then
there is a strong alignment b/w the stator n rotor poles
and hence the alignment torque is greater than the starting
torque.....so magnetic locking takes place b/w the stator n
rotor teeth........

Is This Answer Correct ?    11 Yes 1 No

Answer / souhadri

To avoid the cogging which makes the rotor not to start.

Is This Answer Correct ?    9 Yes 0 No




Answer / gundra chakrababu

if the stator and rotor have same umber of poles,the harmonics produced in them are also of the same order.as these harmonics slip past each other, pulsating torques are produced,if the speed of these harmonics coincide,the stator & rotor poles would lock each other.this condition is called "cogging".under this condition,the motor would crawl at a subsynchronous speed and develops a synchronous torque.

Is This Answer Correct ?    0 Yes 0 No

Post New Answer



More Electrical Engineering Interview Questions

i am electrical and elctronics engg passed out in 2009 want to attend for reliance placements.plz send me apttitude ,technical and hr question answers to my mail plz. my mail id-kat.bindas@gmail.com

0 Answers  


Can we use a Potential Transformer for Auxilliary Power supply( Spring charge Motor, Lighting etc)?

1 Answers  


sir, my question is that if we start any three phase induction motor with star connection.will be current taken ? please send a formula.

4 Answers   ABB,


PID controller details

1 Answers  


What happen to generator if i have unbalanced load?

0 Answers   Sail, TCS, Reliance Energy,


why we use the fuse in only one wire? althrough in ac current the current flows in both directions. why the neutral wire can be taken half the magnitude of phase wire while same current returns from neutral wire?

2 Answers   Bhel,


A 100KVA SINGLE PHASE TRANSFORMER 10000/200V,50HZ REQUIRES 300V AT HV SIDE TO CIRCULATE FULL LOAD CURRENT WITH LV SHORT CIRCUITED.THE INTAKE IS 1000W.THE % OF REGULATION ON FULL LOAD AT 0.8 PF LAGGING WILL BE HOW MUCH AND THE SECONDARY TERMINAL VOLTAGE ON 0.8 PF LEADING WILL BE

0 Answers   IAS,


How much must be gape bitween 2 cable on cable tray?

1 Answers   El Seif,


HOW COULD A SINGLE PHASE INDUCTION MOTOR ROTATE IN OPPOSITE DIRECTION???

3 Answers  


What is the purpose of taking Capacitance and Tan Delta Test in Transformer bushing?

1 Answers  


why it is in star to delta form of Synchrounus generator and delta to star form of Generator Transformer (or step up transformer)

1 Answers  


What is the range of the stator resistance of 3 phase induction motor?

1 Answers  




Categories
  • Civil Engineering (4554)
  • Mechanical Engineering (3668)
  • Electrical Engineering (15588)
  • Electronics Communications (2623)
  • Chemical Engineering (715)
  • Aeronautical Engineering (78)
  • Bio Engineering (30)
  • Metallurgy (95)
  • Industrial Engineering (197)
  • Instrumentation (2846)
  • Automobile Engineering (135)
  • Mechatronics Engineering (41)
  • Marine Engineering (60)
  • Power Plant Engineering (162)
  • Engineering AllOther (1321)