Here is presenting circuit of autocut that is used mostly in manual voltage stabilizer. This is a protection circuit that protects electrical appliances from high voltage. This circuit connected with the output of stabilizer. When voltage increase above from the required set level then this circuit activates the relay and then the output is disconnected and not risk of damaged by the high voltage. Circuit is easy and simple.
Use either 0-18v or 9-0-9v transformer of 500ma. Connect all components as given diagram. In normal supply the relay will deactivated mode , but at when the voltage crosses a fixed voltage then relay automatic activated and NO (normally open) pin of relay will connected. Connect the Load with the NC pin of relay.
After full connection completed Give power supply and adjust the autocut by moving preset at which voltage level you want to set .Use Capacitors of minimum 50v value, it should not less than 50v because in the circuit high voltage supply flows. If you use 12-0-12v transformer then use 24v relay.
Here is another simple circuit of Autocut For manual stabilizer. In this circuit there are small changing from first circuit. if you use 12-0-12 transformer then use 24v relay. You can also check this circuit by connecting with 0-12 transformer with 12v relay. Use 500ma to 1 A Transformer.