In case of __________ speed control by injecting e.m.f. in the rotor circuit is possible,

The main aim behind cooling the digested chip at the bottom portion of the digestor by injecting cold black liquor is to

A

Avoid mechanical weakening of fibre

B

Remove lignin by way of crystallisation

C

Increase the cellulose content

D

None of these

Rotor rheostat control method of speed control is used for

A

Squirrel-cage induction motors only

B

Slip ring induction motors only

C

Both (A) and (B)

D

None of the above

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

Insertion of reactance in the rotor circuit

A

Reduces starting torque as well as maximum torque

B

Increases starting torque as well as maximum torque

C

Increases starting torque but maximum torque remains unchanged

D

Increases starting torque but maximum torque decreases

In deriving ac equivalent circuit for an amplifier circuit we short circuit

A

All resistors

B

All transistors

C

All inductors

D

All capacitors

Out of the following, the highest emf for a given temperature is generated by the __________ thermocouple.

A

Chromel - alumel

B

Iron - constantan

C

Platinum - platinum + rhodium

D

Copper-constantan

The respective ratio between the speed of a speed of the car, bus and train is 5 : 9 : 6. The average speed of the car, bus and train is 72 km/hr together. What is the average speed (km/h)of the car and the train together?

A

82

B

72

C

67

D

84

In pneumatic control systems the control valve used as final control element converts

A

Pressure signal to electric signal

B

Pressure signal to position change

C

Electric signal to pressure signal

D

Position change to pressure signal

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

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 case of __________ speed control by injecting e.m.f. in the rotor circuit is possible,

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