Electrolyte capacitor: short duty
Oil capacitor: Continuous duty
How the optimum starting and running characteristics
is obtained in the two-value capacitor motor?
Optimum starting and running characteristic
The two capacitors are in parallel during starting in the two-value capacitor motor. When the motor speed reaches 75% of the full load speed, the centrifugal switch open and only one capacitor of continuous duty remains in the circuit.
What should be rating of starting capacitor as
compared to running capacitor in the two-value capacitor motor?
The rating of starting capacitor (Short duty rating) is approximately 10
to 15 times that of running capacitor (Continuous duty rating).
State the salient features of the two-value capacitor
motor.
Salient features of two value capacitor motor
Noiseless operation
High efficiency
High power factor
Overload capacity up to 125%
Ability to start against heavy load
How the phase splitting is done in the shaded pole
induction motor?
The phase splitting in the shaded pole induction motor is done by
induction.
Which type of stator and rotor the shaded pole
induction motor consists of?
Shaded pole induction motor
Stator: Salient pole
Rotor: Squirrel cage
Where the shading ring is placed in the shaded pole
induction motor?
Shading ring
The stator of the shaded pole consists of salient poles. The salient
pole has small cut across the laminations approximately one third distance from
one end and shading ring is placed on this cut.
State the direction of flux rotation in the shaded
pole motor?
Unshaded pole to shaded pole
State the salient features of the shaded pole motor.
Salient features : Low efficiency (5% up to 35%), Low overload capacity & Low starting
capacity
State the applications of the salient pole motor.
Application : Small toys, Hair dryers, Ventilators, Electrical clocks, Small fan, Advertising
display boards, Phonograph turntables
Whether the direction of shaded pole motor can be
reversed? Why?
The direction of the shaded pole motor cannot be reversed due to fixed
position of shaded ring.
Describe the different types of repulsion motor.
Types of repulsion motor : Repulsion motor, Compensated repulsion motor, Repulsion
start induction run motor, Repulsion induction motor
Which type of construction does the repulsion motor
consist of?
Repulsion motor
Stator: Salient pole, non – distributed winding
Rotor: Similar to dc armature
Commutator and carbon brushes
On which parameter the armature induced emf depends in
the repulsion motor?
The armature induced emf in the repulsion motor depends upon the
position of the short-circuited brushes.
What is reason behind the name of motor called as
‘repulsion motor’?
Repulsion motor
The rotor of the repulsion motor rotates due to repulsion force between
stator N pole and rotor N pole (or stator S pole and rotor S pole) therefore it
is called as repulsion motor.
On which parameter the starting torque of the
repulsion motor depends?
The starting torque of the repulsion motor depends upon the amount of
brush shift.
Which method is used to control speed of the repulsion
motor?
The speed control of the repulsion motor depends upon brush shift.
Describe the function of compensating winding in the
compensated repulsion motor.
Function of compensating winding
Provides better speed regulation
Improve power factor
Where the compensating winding is provided in the
compensated repulsion motor?’
The compensating winding is provided in the inner slot of the main pole
and it is connected in series with armature winding.
How many brushes the compensated repulsion motor
consists of?
The compensated repulsion motor consists of two pair of brushes.
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