200 Important Single Phase Induction Motor MCQ Question & Answer | PDF Free Download
1.A repulsion motor is equipped with
- ASlip rings
- BCentrifugal switch
- CCommutators and brushes
- DAll of the above
2.The commutation of repulsion motor is at its best
- ADuring starting
- BWhen runs near synchronous speed
- CWhen runs at 50% of synchronous speed
- DWhen run at 150% of synchronous speed
3.In a repulsion motor, commutator provides a means of connecting the
- AStator windings
- BArmature windings
- CStarting winding
- DNone of these
4.In a repulsion motor the brushes are connected
- ATo the external supply
- BTo each other short circuited
- CTo the stator winding
- DNone of the above
5.The torque speed characteristic of a repulsion motor resembles
Which of the following dc motor characteristic?
- ASeparately excited
- BShunt
- CSeries
- DCompound
6.In a single-phase repulsion motor power factor is
- Aalways leading
- Bhigh at low speed
- Chigh at high speed
- Dalways unity
7.In a repulsion motor by shifting the brush position
- ASpeed and direction of rotation can be controlled
- BOnly speed can be controlled
- CSpeed, torque and direction of rotation can be controlled
- DOnly torque can be controlled by varying the speed at constant output power
8.In a repulsion motor, torque developed will be zero when brush axis is at _____electrical degree to the field axis
- A0
- B90
- C45
- DBoth (a) and (b)
9.In a repulsion motor speed control is affected by varying the
- AImpressed voltage
- BPosition of brushes
- CSupply frequency
- DEither (a) and (b)
10.Direction of rotation of a repulsion motor is reversed by
- AInter changing the supply leads
- BShifting the brushes round the commutator
- CEither (a) or (b)
- DNone of these
11.A repulsion start induction motor operates as an induction motor when
- ACommutator segments are short circuited
- BBrushes are short circuited
- CStator is short circuited
- DShort circuiting device is disconnected
12.The short-circuiting device in a repulsion start induction motor operates by
- AMagnetic attraction
- BCentrifugal force
- CCirculating currents
- DNone of the above
13.Which of the following motors is not a synchronous motor?
- AHysteresis
- BRepulsion
- CInductor
- DReluctance
14.A single-phase reluctance motors
- AHas salient pole rotor structure and runs at sub synchronous speed
- BHas salient pole rotor structure and runs at super synchronous speed
- CHas salient pole rotor structure and runs at synchronous speed
- DHas non salient pole rotor structure and runs at synchronous speed
15.Reluctance torque is the
- ATorque developed in a given synchronous motor as a function of field excitation and the sine of the torque angle
- BTorque developed by salient pole synchronous or synchronous induction motors due to variations in air gap produced by armature reaction
- CTorque developed by non-salient pole asynchronous motor
- DTorque developed by none of the above
16.The torque of a reluctance motor can be effectively increased by
- AIncreasing reluctance of the magnetic circuit along the direct axis
- BDecreasing reluctance of the magnetic circuit along the quadrature axis
- CIncreasing the ratio of quadrature axis reluctance to direct axis reluctance
- DDecreasing the ratio of quadrature axis reluctance to direct axis reluctance
17.Hysteresis motor is a
- ASynchronous induction motor
- BSingle phase induction motor
- CSingle phase synchronous motor without any salient pole and without dc excitation
- DSingle phase synchronous motor with salient poles and without dc excitation
18.Hysteresis motor operates on the principle of
- AHysteresis loss
- BEddy current loss
- CElectromagnetic induction
- DMagnetization rotor
19.The rotor of a hysteresis motor is made of magnetic material having area of hysteresis loop
- ALarge
- BVery small
- CMedium
- DAny of the above
20.The rotor of a hysteresis motor is built up of
- ACast iron sheet
- BA group of specially hardened steel rings
- CThink silicon steel laminations
- DThin ?-metal laminations