Working principle of one Xipu STR soft starter controlling two motors

Using one STR soft starter to control two motors does not mean starting them at the same time. Instead, one motor is started and the other is kept as a standby. The circuit is shown in the figure below.

How it works

If a soft starter is used to control a motor, the motor M2 in the figure below can be cancelled. The secondary control circuit composed of KM1, KM2, etc. is shown in the wiring diagram of a soft starter controlling a motor.

The figure below shows a wiring diagram of a soft starter controlling two motors. This circuit is connected to a part of the control circuit outside the soft starter, and the motor is selected for use and standby through the conversion switch SA. SA is turned to "2" to select motor M1 as standby. When QF is connected at the current position as shown in the figure below, the AC contactor KM1 coil is energized and attracted, and its main contact KM1-3 is closed to prepare for starting motor M1. The indicator light HI. l lights up, and then press the RUN key on the STR operating keyboard to start the motor: press the STOP key to stop the motor. The JOG button is set by the user according to the needs. The operating keyboard does not have this function and needs to be installed separately.