How does centrifugal switch opens in capacitor start induction motor?
When motor reaches about 70% of its rated speed then due to centrifugal action switch get open
There are 2 types of capacitor including starting capacitor and running capacitor running capacitor are used to improve the power factor of motor. starting capacitor used in split phase induction motor . starting capacitor may isolate from motor,s starting winding through of centrifugal switch after getting motor 90% of it,s rated speed.
A capacitor start motor is a split phase motor that uses a capacitor in series with the start winding to cause a greater phase shift, resulting in greater starting torque. It uses a centrifugal switch to switch out the start winding and capacitor once the motor is up to speed. I assume this switch is what you're referring to as a "relay".
What is used on a single phase induction motor to disconnect the start winding after the motor starts?
A start capacitor is wired in series with the motor's start winding via a centrifugal start switch. The switch disconnects the capacitor and start winding once the motor has reached a pre-determined minimum speed. The motor then continues to run on its main field winding. A different design uses a "start-and-run" capacitor which remains in circuit whilst the motor is running.
The single phase induction motors are made self starting by providing an additional flux by some additional means. Now depending upon these additional means the single phase induction motors are classified as: 1.Split phase induction motor. 2.Capacitor start inductor motor. 3.Capacitor start capacitor run induction motor. 4. Shaded pole induction motor.
A capacitor-start motor is one in which the capacitor is in the circuit only during the starting period: the capacitor and its auxiliary "start" winding are disconnected automatically by a centrifugal switch or other device when the motor reaches a predetermined speed. A capacitor start-and-run motor is one in which the capacitor remains in-circuit during both start-up and running periods of operation.