Power Circuit
Control Circuit
Circuit Operation
When the start button of the direct-on-line starter is pressed its contacts a3-a4 close, the contactor coil C is energised which causes it’s main contacts on terminals 1-2, 3-4 and 5-6 to close, it’s normally open auxiliary contact on terminals 13-14 also closes. The auxiliary contact maintains power to the contactor coil when the start button is released. Power is connected from the power supply to the motor terminals and the motor will start and accelerate to full speed.
To stop the motor the stop button is pressed its contacts a1-a2 open which de-energises the contactor, thus stopping the motor by removing its power supply and resetting the control circuit.