What will happen if supply to three phase motor is given
wiyhout inerting rotor in it?How much current it will draw?
Answers were Sorted based on User's Feedback
Answer / rajendran
With out the presence of the rotor there will not be any
back emf (In opposition to the supply voltage)....
So the stator winding will draw very high currents from the
mains and the fuses will blow immediately....
| Is This Answer Correct ? | 15 Yes | 2 No |
Answer / chitalima c christopher
To start with; A THREE PHASE INDUCTION MOTOR in operation
behaves just like a transformer except in a motor the rotor
is introduced, therefore a stator without a rotor will
behave just like a transformer on no load meaning it will
only draw a minimum excitation current which will be of
very small value
| Is This Answer Correct ? | 4 Yes | 0 No |
Answer / xyz
Normally, when a motor is switched on, it takes a heavy
current (6 to 7 times the rated current of the motor).This
is because there is no back emf. Then the rotor starts
rotating and picks up speed. As the speed increases and
reaches the rated speed, the back emf increases and the
current decreases and reaches the normal value.
When a motor is switched on without the rotor,the situation
is similar to the one that exists at starting time. There
is no back emf and hence the current will be heavy.Since
there is no rotor, there is no question of back emf. Hence,
if the protection does not trip the supply, the winding
will burn.
You can use this as a project for your science exhibition.
You put the motor (without the rotor) in such a way that
the axis is vertical.Now the vacant space created by the
removal of the rotor is like a cylinder. Close the bottom
part with a plate. Now you can put coins in that
cylinder.Apply a small voltage to the motor winding to
create the revolving magnetic field.The coins will start
moving in the direction of the revolving magnetic field.
| Is This Answer Correct ? | 5 Yes | 1 No |
Answer / pratheesh
It will take only very little amound of current to
develope a magnetic field in the stator.
I dont know the percentage.
| Is This Answer Correct ? | 4 Yes | 3 No |
Answer / siva rao
mr.Rajendran your site tfrs are all closed with sec load?
ok.the machine will draw omly magnetizing current of very
few amps.
| Is This Answer Correct ? | 1 Yes | 0 No |
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