B. cogging

C. humming

D. hunting

A. e.m.f. injection in rotor eueuit

C. None of the above

D. Cascade operation

A. less than number of poles in stator

C. zero

D. more than the number of poles in stator

A. stator reactance

C. rotor leakage reactance

D. the reactive lagging magnetizing current necessary to generate the magnetic flux

A. two parallel windings in stator

C. two rotors moving in oppsite direction

D. two series windings in stator

A. stator resistance test

C. no-load test only

D. noue of the above

A. none of the above

C. to short circuit the starting resistances in the starter

D. to short circuit the stator phase of motor to form star

B. rotor speed is less than the synchronous speed of the field and are in the same direction

C. magnetic field and rotor rotate in opposite direction

D. none of the above

A. self-starting with high torque

B. self-starting with zero torque

D. non-self starting

A. 200 Hz

B. 0.2 Hz

C. 50 Hz

A. By injecting e.m.f. in the rotor circuit

B. Rotor rheostat control

D. By operating two motors in cascade

A. absent

B. large

D. infinity

B. straigth line

C. parabola

D. hyperbola

A. twice the full load torque

C. equal to full load torque

A. increasing slip

B. increasing current

D. none of the above

A. any of the above

C. bigger

D. same

A. double cage rotor

C. any of the above

D. short-circuited rotor

A. copper losses

B. transformation ratio

D. power scale of circle diagram

A. dependent on the shaft loading

B. dependent on the number of slots

D. none of the above

A. Induction motor

C. Synchronous motor

D. D.C. shunt motor

B. changing number of poles

C. reducing supply voltage

D. changing supply frequency

B. Block rotor test and no-load test

C. Block rotor test only

D. No load test only

B. power factor

C. output

D. frequency

A. Squirrel-cage induction motor

C. Both A. and (b)

D. None of the above

B. 60 to 90%

C. 99%

D. 95 to 98%

A. increases starting torque but maxi-mum torque decreases

B. increases starting torque as well as maximum torque

D. increases starting torque but maxi-mum torque remains unchanged

A. proportional to the square of the slip

C. inversely proportional to slip

D. none of the above

B. aluminium

C. silicon steel

D. bronze

A. auto-transformer starter

C. using DOL starter

D. proper ventilation

B. rotor power factor

C. rotor current

D. rotor e.m.f.

A. in the opposite direction as the direction of the rotating field

B. in any direction depending upon phase squence of supply

A. iron losses in motor will be negligible as compared to that in rotor

C. iron losses in stator will be negligible as compared to that in rotor

D. iron losses in stator will be less than that in rotor

B. reduce eddy currents

C. reduce accumulation of dirt and dust

D. reduce windage losses

A. its power factor remains constant

B. its power factor goes on decreasing

C. its power factor goes on increasing even after full load

A. pulling the motor directly on line without a starter

C. locking of rotor due to harmonics

D. starting the motor on load which is more than the rated load

A. The torque produced will be very large

B. The slip of the motor will be 5%

C. The rotor will run at very high speed

A. at the unit value of slip

B. at the value of the slip which makes the rotor reactance half of the rotor

D. at the zero value of slip

A. the magnetising current of the rotor will decrease

C. speed of motor will increase

D. the windage losses will increase

A. graphite

B. mineral oil

D. molasses

A. zero frequency

B. the same phase as the rotor e.m.f.

C. high value for the satisfactory speed control

A. rotor conductors are connected to insulation

B. rotor conductors are kept open

D. rotor conductor ends are short-circuited through slip rings

A. frequent starting, stopping and reversing is required

B. high starting torque is needed

C. speed control is required

B. Cast iron bearings

C. None of the above

D. Bush bearings

A. slip ring induction motor

C. both A. and (b)

D. none of the above

B. running torque

C. line voltage

D. slip

A. 0.04%

C. 0.40%

D. 14%

A. synchronous motor

B. D.C. compound motor

C. D.C. series motor

A. 2 poles

C. 8 poles

D. 4 poles

B. 0.5 leading

C. unity

D. 0.2 leading

B. high speed motors

C. low horse power motors

D. variable speed motors