This DC electronic fuse need not be replaced. It can repair just press one of the S1 button start / restart. Once you press S1, the thyristor T1 triggers and current flows to the load of consumers through T1 and RS resistance. Even after releasing the start button, the current continues to flow as long as the current value does not sink below a certain level.
The current flowing through the thyristor T1 will sink below the level of exploitation, when the current is diverted through the 2N3055 transistor T2. T2 and RS are built into the electronic circuit fuse for this purpose. If the voltage drop exceeds RS over the activation voltage base-emitter diode of T2, the transistor thus avoiding the thyristor. The value of the resistance of the RS must be at least 0.2 W. This should be sized to the product of the RS, multiplied by the value of the maximum current is equal to 0.7 volts.
After passing through the T1 T2, the current flowing through the thyristor sinks below the portfolio and the T1 is turned off. This in turn causes the voltage drop across the resistor RS to sink below the activation voltage base-emitter and the transistor T2 is turned off. The end result is the closure of the entire circuit. The DC fuse can be reactivated by pressing the start / restart.
The value of the resistor R1 is dependent on the supply voltage. Multiply the supply voltage of 1 KW to get the value of R1. Connect the DC circuit electronic fuse PLUS line of customer load. The drop in the circuit coltage is less than 1 volt.