The mechanical displacement of the rotor with respect to the stator, in polyphase multipolar synchronous motors running at full load, is of the order of

A 4 pole 50 Hz induction motor is running at 1300 rpm. Find the speed of stator magnetic field with respect to the rotor?

A

200 rpm

B

1500 rpm

C

1300 rpm

D

1700 rpm

In which of the following motors the stator and rotor magnetic field rotate at the same speed ?

A

Universal motor

B

Synchronous motor

C

Induction motor

D

Reluctance motor

In which of the following motors the stator and rotor fields rotate simultaneously ?

A

D.C. motor

B

Reluctance motor

C

Universal motor

D

Synchronous motor

When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor

A

remains same as the original value

B

decreases to half the original value

C

tends to becomes zero

D

increases to two times the original value

The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as

A

locked-rotor torque

B

synchronous torque

C

pull up torque

D

reluctance torque

Multipolar neurons are

A

Purkinje cells of the cerebellum

B

Pyramidal cells of the cerebrum

C

Amacrine cells of the retina

D

Brush cells of the cochlear nucleus

E

Olfactory receptor cells of the nasal mucosa

Multipolar neurons are found in the

A

Motor cells of the spinal cord

B

Peripheral nerves

C

Posterior root ganglia

D

Vestibular ganglia

E

Retina

The standard full-load power factor ratings for synchronous motors are

A

zero or 0.8 leading

B

unity or 0.8 lagging

C

unity or 0.8 leading

D

unity or zero

The power input to an induction motor is 50 kW when it is running at 4% slip. If the stator resistance and core losses are neglected, the rotor copper loss is

A

30 kW

B

20 kW

C

2 kW

D

4 kW

When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop

A

inductor motor torque

B

induction generator torque

C

synchronous motor torque

D

d.c. motor toque

The mechanical displacement of the rotor with respect to the stator, in polyphase multipolar synchronous motors running at full load, is of the order of

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