Electrical Machines Speed Control Dc Motors Online Exam Quiz
Electrical Machines Speed Control Dc Motors GK Quiz. Question and Answers related to Electrical Machines Speed Control Dc Motors. MCQ (Multiple Choice Questions with answers about Electrical Machines Speed Control Dc Motors
A laboratory group was working with a set of 3-hp shunt DC motor. But there was a mistake that it was fused with a 0.3A fuse instead 3A fuse. Then it was started _________
Options
A : a flash occurred instantly
B : it ran for 3s and fuse was blown
C : it ran normal
D : none of the mentioned
Run-away for large DC machine is avoided by using _________
Options
A : a turn or two of cumulative compounding
B : compensating winding
C : stablizer winding
D : all of the mentioned
Small DC motors have best speed control by _________
Options
A : armature voltage control
B : field resistance control
C : any of the methods
D : none of the mentioned
Armature voltage control works for speeds _____ base speed and field resistance control works well for speed _____ base speed.
Options
A : below, above
B : above, below
C : above, above
D : below, below
Ward-Leonard system of system of speed control is not recommended for _________
Options
A : constant speed operation
B : Wide speed
C : frequent-motor reversed
D : very slow speed
Mark the wrong option. Which of the following cause and effect behaviour in speed control is correct when field resistance is increased.
Options
A : Decrease in flux
B : Increase in armature current
C : Increase in EMF
D : Decrease in speed
At a very low speed, increase in field resistance will _________
Options
A : decrease the speed of motor
B : increase the speed of motor
C : not have signicant effect on speed
D : no effect
Why does DC motor sometimes run too fast when under-loaded?
Options
A : Due to weak field
B : Due to high line voltage
C : Due to brush-shifted to neutral
D : All of the mentioned
To implement armature voltage control, it must be ensured that _________
Options
A : it is used on separately excited machine
B : it is used on shunt machine
C : it is used on series machine
D : any of the mentioned machine
The PWM control of DC motor varies _________
Options
A : linearly with speed
B : inversely with speed
C : parabolically with speed
D : exponentially with speed
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