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WorksheetsSINGLE PHASE INDUCTION MOTOR
Total questions: 15
Worksheet time: 12mins
What creates a rotating magnetic field in an induction motor?
The angular speed of the motor
Three phase current flowing in the rotor
Three phase current flowing in the stator
A single phase current flowing in both the rotor and the stator
A single phase induction motor employs ________rotor
squirrel cage
wound
either squirrel cage or wound
none
The purpose of starting winding in a single phase induction motor is to_____
reduce losses
limit temperature rise of the machine
produce rotating flux in conjunction with main winding
none
The direction of rotation of a single phase motor may be achieved by
changing over the supply phase and neutral
reversing the connections to both start and run windings
reversing the connections to either start or run windings
reversing the connections to the centrifugal switch.
What component is required to control the starting capacitor in a single phase induction motor?
shunt coil
thermal trip
discharge resistor
centrifugal switch
In a split-phase motor, the running winding should have
High resistance and low inductance
High resistance and High inductance
Low resistance and high inductance
Low resistance and low inductance
If the capacitor of a single-phase motor is short-circuited
The motor will not start
The motor will run in the same direction at a reduced speed
The motor will run in the reverse direction
None of the above
In a split-phase motor
Both starting and running windings are connected through a centrifugal switch
Centrifugal switch is used to control supply voltage
The running winding is connected through a centrifugal switch
The starting winding is connected through a centrifugal switch
The torque developed by a single-phase motor at starting is
less than the rated torque
More than the rated torque
zero
None of the above
A centrifugal switch is used to disconnect ‘starting winding when motor has
Picked up 10% speed
Picked up 20% speed
Picked up 5 – 10% speed
Picked up 50 – 70% speed
The direction of rotation of a split-phase motor can be reversed by reversing the connection of
Starting winding
Running winding
Either 1 or 2
None of the above
In a capacitor start single-phase motor when the capacitor is replaced by a resistance
Motor will consume less power
Motor will continue to run in the same direction
Motor will stop
None of the above
The wattage of the motor which we use for domestic sewing machine will be
100 W - 150W
40 - 75W
10 - 30W
5 - 10W
In a ceiling fan employing capacitor run motor
Primary winding surrounds the secondary winding
Secondary winding surrounds the primary winding
Either 1 or 2
None of the above
If a single-phase induction motor runs slower than normal, the most likely defect is
Short circuit winding
Open circuit winding
Worn bearing
All of the above
