For starting a D.C. motor a starter is required because

It is advisable to avoid line starting of induction motor and use starter because

A

It will run in reverse direction

B

It will pick up very high speed and may go out of step

C

Motor takes five to seven times its full load current

D

Starting torque is very high

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

A direct on line starter is used: for starting motors

A

Up to 5 H.P.

B

Up to 10 H.P.

C

Up to 15 H.P.

D

Up to 20 H.P.

The coils of D.C. motor starter are wound with wire of

A

Copper

B

Kanthal

C

Manganin

D

Nichrome

In a manual shunt motor starter

A

Over load relay is connected in series and no volt relay in parallel with the load

B

Over load relay is connected in parallel and no volt relay in series with the load

C

Over load relay and no volt relay are both connected in series with the load

D

Over load relay and no volt relay are both connected in parallel with the load

In a star-delta starter of an induction motor

A

Resistance is inserted in the stator

B

Reduced voltage is applied to the stator

C

Resistance is inserted in the rotor

D

Applied voltage per stator phase is 57.7% of the line voltage

The starter motor is driven by

A

Chain drive

B

Gear drive

C

Flat belt drive

D

V-belt drive

While starting a synchronous motor by induction motor action, field winding is usually

A

connected to D.C. supply

B

short-circuited by low resistance

C

kept open-circuited

D

none of the above

Of the 120 households in an area, 55 have cars, 35 have motor bikes, and 20 have both cars and motor bikes. How many of the households in the area have neither cares nor motor bikes?

A

110

B

90

C

50

D

30

A motor pool has 300 vehicles of which 30% are trucks. 20% of all the vehicles in the motor pool are diesel, including 15 trucks. What percent of the motor pool is composed of vehicles that are neither trucks nor diesel?

A

165%

B

90%

C

65%

D

10%

For starting a D.C. motor a starter is required because

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