Motor forward and reverse control wiring diagram (1)

The circuit diagram shared in this article shows the motor forward and reverse control wiring diagram, and it uses a double interlock with a button and a contactor to assist electric shock, with a self-holding control method, and the control loop voltage is line voltage. In principle, there is no problem and basic functions can be achieved. However, the normally closed contact of the thermal relay is generally connected between the contactor coil and the power supply "2". The purpose of this is to disconnect the normally closed contact after the thermal relay operates. At this time, the entire control loop except one end of SB1 (" 1") and one end ("2") of the thermal relay's normally closed contact are electrified, other components are uncharged, especially the coil of the contactor is uncharged, which effectively reduces the risk of electric shock to personnel due to inspection actions. It can also completely de-energize the coil. Because the thermal relay usually operates due to the main circuit current being too large for a long time, causing the temperature of the bimetallic piece in the relay to reach the operating value, the protection will act and cut off the main circuit to protect the motor and contactor.