In repulsion motor, zero torque is developed when

In repulsion motor, maximum torque is developed when

A

brush axis is at 45° electrical to the field axis

B

brush axis coincides with the field axis

C

brush axis is at 90° electrical to the field axis

D

none of the above

Speed torque characteristic of a repulsion induction motor is similar to that of a D.C.

A

shunt motor

B

series motor

C

compound motor

D

separately excited motor

In repulsion motor direction of rotation of motor

A

Is opposite to that of brush shift

B

Is the same as that of brush shift

C

Is independent of brush shift

D

None

A repulsion motor is equipped with

A

slip rings

B

commutator

C

both (A) and (B)

D

none of the above

The purpose of stator winding in the compensated repulsion motor is to

A

provide mechanical balance

B

improve power factor and provide better speed regulation

C

prevent hunting in the motor

D

eliminate armature reaction

Which of the following statements regarding repulsion-start induction motor is incorrect ?

A

It requires more maintenance of commutator and other mechanical devices

B

It makes quite a bit of noise on starting

C

In fractional horse power motors, it has replaced the capacitor motors

D

It is not easily reversed

The repulsion start induction run motor is used because of

A

good power factor

B

high efficiency

C

minimum cost

D

high starting torque

In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will

A

Remain unchanged

B

Reduce to one-fourth value

C

Increase four folds

D

Be doubled

The ratio of starting torque to running torque in a synchronous motor is

A

zero

B

one

C

two

D

infinity

Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters. REPULSION :

A

combination

B

elongation

C

attraction

D

oscillation

In repulsion motor, zero torque is developed when

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