## Electrical Machines An induction motor has a rotor resistance of 0.002 Ω / phase. If the resistance is increased to 0.004 Ω / phase then the maximum torque will

reduced to half
increase by 200%
increase by 100%
remain unaltered

## Electrical Machines To have sparkless commutation, the armature reaction effect in a DC machine is neutralized by

compensating winding and commutating poles.
increasing field excitation.
fixing the brush axis inline with the pole axis.
shifting the brush axis from GNA to MNA.

## Electrical Machines What is the actual arrangement of series wound generator?

Armature and field both are connected.
Armature and field both are in series with the load.
Armature and field both are parallel.
Armature winding is in series with load.

## Electrical Machines In which of the following DC Motor the ratio of starting torque to full load torque is minimum?

Differential compound motor.
Cumulative compound motor.
Shunt motor.
Series motor.

## Electrical Machines The following statements relate to compensating winding (CW) and interpole winding (IW) of a dc machine : 1. CW neutralizes the armature reaction under a pole pitch 2. IW is connected in series with armature circuit 3. IW produces mmf in the commutating zone only 4. CWmmf is directed along the brush axis 5. Mmf produced by IW is equal to armature mmf From these, the correct statements are

2, 3, 4, 5
1, 2, 3, 4 and 5
2, 3, 4
1, 3, 4, 5

## Electrical Machines Number of tappings for each equalizer ring is equal to

number of poles.
number of pole pairs.
number of commutator segments.
number of parallel paths.