Related Questions

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 tests will be suitable for testing two similar D.C. series motors of large capacity?
A Swinburne's test
B Hopkinson's test
C Field test
D Brake test
In case of conductively compensated D.C. series motors, the compensating winding is provided
A As separately wound unit
B In parallel with armature winding
C In series with armature winding
D In parallel with field winding
When two D.C. series motors are connected in parallel, the resultant speed is
A More than the normal speed
B Loss than the normal speed
C Normal speed
D Zero
During rheostatic braking of D.C. series motors
A Motor is run as a generator
B Motor is reversed in direction
C Motor is run at reduced speed
D None of these
In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to
A improve power factor
B increase overload capacity
C reduce fluctuations in torque
D to improve torque
Which of the following motors has series characteristics?
A Shaded pole motor
B Repulsion motor
C Capacitor start motor
D None of the above
Starters are used with D.C. motors because
A These motors have high starting torque
B These motors are not self-starting
C Back e.m.f. of these motors is zero initially
D To restrict armature current as there is no back e.m.f. while starting
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.
Blocked rotor test on induction motors is used to find out
A Leakage reactance
B Power factor on short circuit
C Short-circuit current under rated voltage
D All of the above

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