Electronic overvoltage relay circuit

Electronic overvoltage relay circuit Author: Source: Update date: 2004-12-15 Number of views: 51 The circuit design is simple. When the power supply voltage exceeds the limit value, it can reliably act to cut off the power supply to ensure that the load does not operate at overvoltage. The circuit is shown below. The power supply for the relay and the thyristor is converted to 24V by the transformer and rectified by D1. The relay and the thyristor are connected in series in the circuit. R1 and R2 are voltage dividing resistors. Adjusting the size of R2 can change the control electrode potential, so that the thyristor can be turned on according to the selected voltage. When the power supply voltage reaches the voltage limited by the thyristor, the thyristor is turned on, the relay operates, the overvoltage indicator light ZD lights up, and the power supply to the load end is cut off. The overvoltage adjustment range should be such that when the power supply voltage is at the normal value, the thyristor does not conduct, and when the power supply voltage exceeds the normal value by 5 to 10%, the thyristor conducts and the relay operates.