SL-322 integrated circuit multi-function protection circuit b

This circuit uses SL-322 integrated circuit . Its output end has several light-emitting diodes and a sensitive relay. According to the number of light emitting diodes, the operating current of the motor
can be read to monitor the operation of the motor . If overcurrent occurs, the sensitive relay will act to realize the shutdown function. In the figure, the potentiometer RP is the output value given potentiometer . By adjusting it, the output current value can be set to any given value in the range of 5 to 50A; to meet the requirements of automatic shutdown. The circuit also has a phase failure protection function.     When the motor is overloaded, the voltage U. rises, pin 6 of SL-322 outputs high potential, the sensitive relay KA closes, the contactor KM releases, and the motor stops. At the same time, the bell HA and the indicator light H send out an alarm signal.     Thermal relay FR serves as overload backup protection and phase failure protection.