How does a Soft Starter Work with Contactor?

Soft starter is an AC motor control device that combines soft start, soft stop, energy saving and multi-function protection. It can be used in place of motor starters to reduce the inrush current surge caused by large loads. So how does a soft starter start and stop a motor with a bypass contactor? ATO assistant will explain to you.

Connect the motor, bypass contactor, control button, power supply and soft start according to the circuit diagram.

• The input power sources L1, L2, L3 are connected to R, S, T of soft start respectively.
• The U, V, W of the bypass contactor are connected to the motor input (soft start output).
• The coil of the bypass contactor is controlled by soft start 1 and 2.
• The emergency stop button and the stop button are connected to the control ports 7, 8 and 10 (common).

After power on, press emergency stop, LCD display 7 and 10 are disconnected, at this time, the RUN button on the panel is invalid.
Press the stop button, then press RUN, LCD display 8 and 10 are disconnected, at this time the motor still cannot run.

When the two control buttons are restored, the soft start can run normally.
Press the "RUN" motor to start acceleration. After accelerating to normal speed, the bypass contactor will pull in.
At this time, the three-phase electricity reaches the motor through the contactor, and the motor runs normally.

When pressing the emergency stop button (7 and 10 off), the motor stops immediately.
Press the stop button (8 and 10 off), the motor also stops running.

Know more details about soft starter works with contactor, please view the video below. ATO automation provides low voltage of 220V, 240V, 380V, 480V, 690V soft starters for 3-phase motors. Buy online now.