In variable speed motor

A A stronger commutating field is needed at low speed than at high speed
B A weaker commutating field is needed at low speed than at high speed
C Same commutating field is needed at low speed than at high speed
D None of the above is correct

Correct Answer: A weaker commutating field is needed at low speed than at high speed

Bissoy MCQ
#Electrical Engineering #D.C. Motors

Related Questions

a motor -cycle covers 40 Km with a speed of 20 km /hr. Find the speed of the motor -cycle for the next 40 km journey so that the average speed of the whole journey will be 30 km / hr.
A 70.0km /hr
B 52.5km /hr
C 60.0km/hr
D 60. 5 km / hr
A motor cycle covers 40 km with a speed of 20 km/hr. Find the speed of the motor cycle for the next 40 km journy so that the average speed of the whole journey will be 30 km/hr?
A 70
B 52.5
C 60
D 60.5
Size of a high speed motor as compared to low speed motor for the same H.P. will be
A Bigger
B Smaller
C Same
D Any 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%
By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?
A Frame
B Shaft
C Commutator
D Stator
One D.C. motor drives another D.C. motor. The second D.C. motor when excited and driven
A Runs as a generator
B Does not run as a generator
C Also runs as a motor comes to stop after sometime
D None of these
Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be
A Level compounded
B Under compounded
C Cumulatively compounded
D Differentially compounded
A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will
A remain same
B go down
C improve
D none of the above
In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will
A Remain unchanged
B Reduce to one-fourth value
C Increase four folds
D Be doubled

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