The armature torque of the D.C. shunt motor is proportional to

If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens

A

This will make armature to take heavy current, possibly burning it

B

This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses

C

Nothing will happen to motor

D

Motor will come to stop

If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens

A

Nothing will happen to the motor

B

This will make armature to take heavy current, possibly burning it

C

This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses

D

Motor will run at very slow speed

In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be

A

Almost negligible

B

Rated full-load current

C

Less than full-load current

D

More than full-load current

The current drawn by the armature of D.C. motor is directly proportional to

A

The torque required

B

The speed of the motor

C

The voltage across the terminals

D

None of the above

If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will

A

Increase

B

Decrease

C

Remain same

D

Become zero

If the field of a D.C. shunt motor gets opened while motor is running

A

The speed of motor will be reduced %

B

The armature current will reduce

C

The motor will attain dangerously high speed 1

D

The motor will continue to run at constant speed

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

A

zero

B

one

C

two

D

infinity

As the load is applied to a synchronous motor, the motor takes more armature current because

A

The increased load has to take more current

B

The rotor by shifting its phase backward causes motor to take more current

C

The back e.m.f. decreases causing an increase in motor current

D

The rotor strengthens the rotating field causing more motor current

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

While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by

A

induction motor torque in field winding

B

induction motor torque in damper winding

C

eddy current and hysteresis torque in pole faces

D

reHetance motor torque due to saliency of the rotor

E

all of the above methods

The armature torque of the D.C. shunt motor is proportional to

Related Questions