Single phase motor starting

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Protection with Motor Circuit Breaker (MCB)

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Operating mode: Same as for direct on line starting instead of fuses and thermal relay you can use a motor circuit breaker with thermal and magnetic trips, a simple but at least as effective component. By pressing Start push button the Q2 contactor coil is energized, the motor will start run and maintains itself after the button Start release, by means of auxiliary Q2 contact, the Stop and Emergency Stop buttons. When overload occur Q1 circuit breaker opens, so the motor is stopped.

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MCB and contactor calculation

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Mcb and contactor Q1, Q2 must be chosen according with your motor rated power that can be found on motor plate. Value for F1 fuse must be at most 1 A.