In a 3 phase squirrel cage induction motor why does rotor
rotate?
will 3 phase transformer rotate like a motor if it is
placed on bearings and powered up? give reason
- 10 Answers
- 25613 Views
- Siemens, I also Faced
- E-Mail Answers
Answer Posted / ranjeet mukherjee
In 3phase induction motor,when 3 phase supply is given,a
rotating and constant magnetic field is developed in the
air gap between rotor and stator.This magnetic field is cut
by rotor bars,so an emf is induced in the rotor bars.As the
rotor is short circuited from both end so a current will
flow in the bars.The direction of this current will be such
that it will oppose the cause which is producing it(Lenz's
Law).Here in this case the cause is the relative speed
between the rotating magnetic field and the standstill
rotor.So the rotor starts rotating in the direction of the
magnetic field so that it cathes the speed of the magnetic
field and reduce the relative speed between them.
Although the principal of working of 3phase induction motor
and transformer are same but in case of transformer there
is no relative speed between primary and secondary windings
magnetic field.Moreover both the windings are placed in
same core and there is no air gap between the magnetic
fields of the windings.Both the flux are in same core.So it
is not possible to rotate a transformer even though it is
placed in bearings.
| Is This Answer Correct ? | 10 Yes | 3 No |
Post New Answer View All Answers
am commissioning the trafo without connecting the neutral therefore unbalance will occur what is the alternative solution for this?
What is purpose of reactor?.What is different between line and bus reactor?
While performing stability test of differintial cts how to know the voltage and current on both side of the transformer?
Where can I get CPWD electrical specifications & Shedule of rates? Please help me
Explain the following and how these are working with PLC Unit 1 I/O Module Card 2 Adaptor Card 3 Ribbon Adaptor 4 I/O bus 5 I/O Devices
at what rate the micro controller increment its timer....is it 1micro seconds or 1/(12*10^6) seconds
how can we calculate the ratio of caustic soda and water in lrs.
Why does curving the pole faces in a dc machine contributes to a smoother dc output voltage from it?
why the voltage and current in a long transmission line are called travelling wave?
Explain (in simple ) - root mean square. whats its role in electrical fundamandal.where its used
it is possible to rotate the DG engine dc starter with wrong polarity connections? why?
What is relation between transmission lines & Communication lines ?
how is the testing of an REF relay? what are the test REF circuit having?
explain remenance . differentiate high remenance type ct & low remenance type ct
How many types are using in 220kv/400 kv swith yard
