The performance of two value capacitor – run motor is characterized by

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ALP CBT 2 Electrician Previous Paper: Held on 23 Jan 2019 Shift 1

Answer 1

Capacitor Start Capacitor Run Motor has a cage rotor, and its stator has two windings known as Main and Auxiliary Windings.
The two windings are displaced 90° in space.
Two capacitors are used in these types of motors.
One is used at the time of the starting and is known as the starting capacitor.
The other one is used for continuous running of the motor and is known as the run capacitor.
So this motor is named as Capacitor Start Capacitor Run Motor or also known as Two Value Capacitor Motor.
It has ability to start heavy loads.

F1 U.B Madhu 31.12.19 D 3

There are two capacitors in this motor represented by CS and CR.
At the starting, the two capacitors are connected in parallel.
Capacitor CS is the starting capacitor and is short time rated. It is electrolytic in nature having large value.
Run capacitor CR has small value with long-time rated and is made of oil-filled paper.
This type of motor is quiet and smooth running.
They have higher efficiency than the motors that run only on the main windings.
They are used for loads of higher inertia requiring frequent starts where the maximum pull-out torque and efficiency required are higher.
They are used in pumping equipment, refrigeration, air compressors, etc.