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WorksheetsSTARTERS IN DC MOTORS
Total questions: 15
Worksheet time: 8mins
Which D.C. motor is preferred for elevators
Shunt motor
Series motor
Differential compound motor
Cumulative compound motor
By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?
Frame
Shaft
Commutator
Stator
A three point starter is considered suitable for
shunt motors
series motors
compound motor
all D.C. motors
Four-point starter is used when
Motor field current is varied in a narrow range
Motor speed is varied in small range
Motor field current is varied over wide range
Can be used anywhere
Which of the following are protective devices in DC motor Starter?
No volt coil
Over Load Coil
Both 1 and 2
None
Which of the following are the disadvantages of a three-point starter?
Field Current Become weak
Disconnect the motor from the supply
The flow of current through the shunt field is decreased.
All of the above
A 3- point starter is used to:
Minimize back emf
Minimize armature current
Maximize armature current
Maximize back emf
What will happen if DC motor is used without starter?
Heavy sparking at brushes
It’ll start smoothly
Will not start at all
Depends on load
Which of the following types of starters are used in DC series motors?
Two-point starters
Five-point starters
three point starter
Four-point starters
In a four-point starter NVC is connected _______ across the supply.
Series
Parallel
Independently
Series Parallel
No load speed of which of the following motors is high
Shunt motor
Series Motor
Cumulatively Compound Motor
Differentially compound motor
For a series motor, field flux is
Proportional to temperature
Constant
Proportional to armature current
Inversely proportional to armature current
Speed of d.c. series motor at no load is
1500 rpm
3000 rpm
infinity
zero
If back e.m.f. suddenly disappears in a d.c. motor
Motor will start as a generator
Motor will stop
Winding will burn due to high armature current
Noting will happen
Torque speed characteristic of a series motor is
Parabola
Rectangular Hyperbola
Linear
None
