Most induction motors are controlled by the direct online starter, however, the heavy motor with the heavy load if there started using direct online starter Huge voltage surge(voltage surge can damage electronic equipment, small machines and the contractor that is supplying the same circuit)because of the high current that is drawn from the supply.
Parts that make up the starter
1) 3 Contactors (main contactor, star contactor and delta contactor)
2) Auxiliary contact(with NC) for each contactor
3) On delay timer
4) Thermo overload relay
5) Control breaker(double-pole)
6) Push-button(2)(start and stop)
When the ON push button starts the circuit by energizing the star contactor(S) and the timer(T) at the same time. The star contactor(S) get energized through NC of the timer(T) through NC of the delta contactor(D).when star contactor(S) is engaged(energized) it closes its auxiliary contact NO through which the main contactor(M) get energized.
The circuit will run for the set period of time normally (a few seconds) and timer (T) will open NC and closes NO through which delt contactor (D) get energized.
NOT because the main contactor(M) is energized through the star contactor(S), we don’t want it(main contactor) to go off when the star contactor is disconnected, that’s why we make a parallel connection between star contact (Y AUX) and main contactor (M AUX2).
Most induction motors are controlled by the direct online starter, however, the heavy motor with the heavy load if there started using direct online starter Huge voltage surge(voltage surge can damage electronic equipment, small machines and the contractor that is supplying the same circuit)because of the high current that is drawn from the supply.
Parts that make up the starter
1) 3 Contactors (main contactor, star contactor and delta contactor)
2) Auxiliary contact(with NC) for each contactor
3) On delay timer
4) Thermo overload relay
5) Control breaker(double-pole)
6) Push-button(2)(start and stop)
When the ON push button starts the circuit by energizing the star contactor(S) and the timer(T) at the same time. The star contactor(S) get energized through NC of the timer(T) through NC of the delta contactor(D).when star contactor(S) is engaged(energized) it closes its auxiliary contact NO through which the main contactor(M) get energized.
The circuit will run for the set period of time normally (a few seconds) and timer (T) will open NC and closes NO through which delt contactor (D) get energized.
NOT because the main contactor(M) is energized through the star contactor(S), we don’t want it(main contactor) to go off when the star contactor is disconnected, that’s why we make a parallel connection between star contact (Y AUX) and main contactor (M AUX2).
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