The diameter of the rotor shaft for an electric motor depends on which of the following ?
(A) r.p.m. only
(B) Horse power only
(C) Horse power and r.p.m.
(D) Horse power, r.p.m. and power factor
In series motor which of the following methods can be used for changing the flux per pole ?
(A) Tapped field control
(B) Diverter field control
(C) Series-parallel control
(D) Any of the above
For which of the following applications motor has to start with high acceleration ?
(A) Oil expeller
(B) Floor mill
(C) Lifts and hoists
(D) Centrifugal pump
Which of the following motors is preferred when smooth and precise speed control over a wide range is desired ?
(A) D.C. motor
(B) Squirrel cage induction motor
(C) Wound rotor induction motor
(D) Synchronous motor
The capacity of a crane is expressed in terms of_______________?
(A) type of drive
(B) span
(C) tonnes
(D) any of the above
A pony motor is used for the starting which of the following motors ?
(A) Squirel cage induction motor
(B) Schrage motor
(C) Synchronous motor
(D) None of the above
When a pure semiconductor is heated, its resistance_________________?
(A) Goes up
(B) Goes down
(C) Remains the same
(D) Can’t say
A semiconductor has ______________ temperature coefficient of resistance?
(A) Positive
(B) Zero
(C) Negative
(D) None of the above
Belted slip ring induction motor is almost invariably used for_________________?
(A) water pumps
(B) jaw crushers
(C) centrifugal blowers
(D) none of the above