Is a induction motor rotate by back emf ? If not , then how it is rotate ?



Is a induction motor rotate by back emf ? If not , then how it is rotate ?..

Answer / chandru

Yes,back emf should be there to run it as an induction
motor.Normally what will happen is, when you give 3 phase
power to stator,rotating magnetic field(rmf) will be
created over it.Inturn,this rmf will induce an emf in rotor
side.According to lenz law,obviously this induced emf will
oppose the cause that produces it.Here, the cause is
relative motion between stator's rotating mag field and
rotor speed.Normally,we will call it as slip.So, it will
try to make that relative motion to zero.Due to this
operation, induction motor will rotate.If suppose,rotor
speed catches the stator's rmf,induction motor will
stop.Finally, the main thing to note here is that, it wont
run without slip.

Is This Answer Correct ?    3 Yes 1 No

Post New Answer

More Electrical Engineering Interview Questions

How many types of faults are there in 3 phase power system?

0 Answers  


Why current flows in nutral? As per theory there should be no current in 3 ph explain.

11 Answers   Bhel,


can v rotate single phase induction motor in both the direction...?

1 Answers  


what is the difference b/w ground & virtual ground?

0 Answers   Accenture,


why in an electrical lab a bulb connected to supply goes off slowly when the main supply is switched off?

2 Answers  






I want formula to calculate cable size as per load given in kw & amp.I searched many sites but didn't right answer.Plz reply me asap.

41 Answers   Armco, BEL, BGS, Biocon, BRB Cable, Crystalline Chemical Industries, DLF, Doshion, Electrical, Gold Roof, L&T, Lanco, MEIL, Oman Cables Industry SAOG, PK Services, Polycab, Sabic, SLV, System Electrical, Tata Motors, UEM, UMIC, Vega, Vertex, Voltas,


can any one tell me about the Extra low voltage systems?From where we give supply to these type of systems??

0 Answers   MCB,


Please clarify, 1. Is it required to lay two runs of GI wire along with Armoured LT cable if it is laid between one big mains (63Amps TPN SDF) to small main (32A TPN SDF) with proper glanding termination? 2. If the armoured cable with proper glanding is laid from DB to CNC machine, is it required to run two runs of body earthing to the Machine from DB? 3.If the armoured cable with proper glanding is laid from Substation to Hangar, distance is approx. 100 mtrs, is it required to do earthing at shop area though the primary termination at substation is earthed through gland.

0 Answers   HAL,


Why there is a current in neutral line

3 Answers   Honeywell,


Do anybody has a design software or tools for the selection and design of electromechanical components???

1 Answers  


why Transformers power mentioned in KVA?. and why Generators and Motors power mentioned in KW?.

10 Answers  


Whether the Dc motor Droping the power factor like AC motor if lot of motor running in factory is it necessary to connect capacitor bank

2 Answers  


Categories
  • Civil Engineering Interview Questions Civil Engineering (5085)
  • Mechanical Engineering Interview Questions Mechanical Engineering (4451)
  • Electrical Engineering Interview Questions Electrical Engineering (16632)
  • Electronics Communications Interview Questions Electronics Communications (3918)
  • Chemical Engineering Interview Questions Chemical Engineering (1095)
  • Aeronautical Engineering Interview Questions Aeronautical Engineering (239)
  • Bio Engineering Interview Questions Bio Engineering (96)
  • Metallurgy Interview Questions Metallurgy (361)
  • Industrial Engineering Interview Questions Industrial Engineering (259)
  • Instrumentation Interview Questions Instrumentation (3014)
  • Automobile Engineering Interview Questions Automobile Engineering (332)
  • Mechatronics Engineering Interview Questions Mechatronics Engineering (97)
  • Marine Engineering Interview Questions Marine Engineering (124)
  • Power Plant Engineering Interview Questions Power Plant Engineering (172)
  • Textile Engineering Interview Questions Textile Engineering (575)
  • Production Engineering Interview Questions Production Engineering (25)
  • Satellite Systems Engineering Interview Questions Satellite Systems Engineering (106)
  • Engineering AllOther Interview Questions Engineering AllOther (1379)