Remote Operating Devices in circuit breaker
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| In Circuit Breaker Used Remote Operating Devices [figure 1] |
Introduction
Tripping coil
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| In Circuit Breaker Used Remote Operating Devices [figure 2] |
The tripping coil is a small electromagnet that helps to release the spring of the moving contact of the circuit breaker.
The structural features of the tripping coil are that it looks like a small motor, its parts are sensing coils or electromagnets, moving magnetic core and spring.
The sensing coil has a moving iron core and is pulled upwards with spring tension.
When the relay sends a signal ,the auxiliary voltage supply makes the tripping coil energized and pulls the moving iron core downwards then the spring of the moving contact of the circuit breaker is released and closes the circuit.
Number of Tripping coil
A circuit breaker has two tripping coils, one coil working if the first tripping coil is not working then relay command sent to another tripping coil simply another tripping coil is the backup support purpose .
Function of Tripping Coils
When the circuit is closed, the three will close the circuit at the same time. If the closing time of the three poles is delayed for any reason, then the system will become unbalanced.
And these two tripping coils are kept in regular maintenance .The working tripping coil and the backup tripping coil operates remote interlocking.
That's the way it works,The relay sends a signal to the first tripping coil and if the first tripping coil does not work in some time deals, the relay sends a signal to the backup tripping coil for opens the circuit.
Tripping coils usually have three leads for two lead inputs for one ground.Figures and diagrams illustrate how the tripping coil looks.
Spring charging motor
Spring charging motor Circuit breakers usually have two springs, one to closing spring and the other to opening spring . An open and close circuit can usually be made with a spring, but for safety reasons and to avoid applying too much force to a spring, the circuit is open and closed with two separate springs.
The charging motor in the circuit breaker is used to tension this closing spring.The type of the charging motor usually uses a universal series motor with a gear box arrangement.
The Motor rating depends on circuit breaker rating. Usually the rating of all these motors is such that the voltage rating is 110-125 or 220-250 VDC or VAC and RPM 2000 to 6000 and wattage 80 to150 starting current 20-40 A and normal current 4-8A starting and normal current depends on the voltage rating.
The motor selection is based on the rating of the circuit breaker because if the rating of the circuit breaker is higher than the spring tension is more then the rating of the motor increases with the rating of the circuit breaker.
Universal motors are commonly used in low rated circuit breakers and squirrel cage induction motors in slightly higher rated circuit breakers.
Closing coil Closing coils look like tripping coils. Structural variation and working tripping are one like coils. The only difference is their work.
The closing coil gives circuit breaker instruction to close the circuit just as the tripping coil makes the circuit trip.Usually the closing spring is held by the iron core of the closing coil.
In real instruction the closing coil pulls down and the moving contact fixed contact is held together by the spring.
Conclusion
Tripping coil is the main part of remote operation in circuit breaker . And the Spring charging motor use for charging the charge the spring.
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