Which of the following motors is preferred when smooth and precise speed control over a wide range is desired?

Usually wide and sensitive speed control is desired in case of

A

Centrifugal pumps

B

Elevators

C

Steel rolling mills

D

Colliery winders

Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?

A

Low cost

B

Wide speed range

C

Stability

D

High starting torque

Which of the following motors is preferred when quick speed reversal is the main consideration?

A

Squirrel cage induction motor

B

Wound rotor induction motor

C

Synchronous motor

D

D.C. motor

Following motor is used where high starting torque and wide speed range control is required.

A

Single phase capacitor start

B

Induction motor

C

Synchronous motor

D

D.C. motor

For reactions in parallel viz A → P (desired product) and A → Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a

A

Batch reactor is preferred over a single CSTR for high yield

B

Tubular reactor is preferred over a single CSTR for high yield

C

Both A and B

D

Single CSTR is the most suitable

Which of the following motors is preferred for tape-recorders?

A

Shaded pole motor

B

Hysteresis motor

C

Two value capacitor motor

D

Universal motor

Which of the following motors is preferred for traction work?

A

Universal motor

B

D.C. series motor

C

Synchronous motor

D

Three-phase induction motor

Which of the following motors are preferred for overhead traveling cranes?

A

Slow speed motors

B

Continuous duty motors

C

Short time rated motors

D

None of the above

For which of the following applications D.C. motors are still preferred?

A

High efficiency operation

B

Reversibility

C

Variable speed drive

D

High starting torque

Which of the following motors is preferred for boom hoist of a traveling crane?

A

Single phase motor

B

Synchronous motor

C

A.slip ring motor

D

Ward-Leonard controlled D.C. shunt motor

Which of the following motors is preferred when smooth and precise speed control over a wide range is desired?

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