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Relay - Power Failure Manual Re-connection System

stop the power supply at the output even the power is recovered after Main Power Failure

The function of this circuit is to stop the power supply at the output even the power is recovered after Main Power Failure. This is important for the valuable equipment and safety.

S1 is the Main Switch of this circuit

S2 is Press Button Switch (No lock). When start up, S2 is pressed and the contacts of the Relay RY1 will be connected. After that RY1 will keep connected even S2 is not pressed.

If Main Power Failure happens, RY1 will be released and will not re-connect before the Main Power recovers and S2 is pressed.


The following demonstration is very dangerous because of LIVE electricity !!!

  • Switch on the Main Power

  • Press the Button Switch

  • The Relay is activated and the light is on

  • Switch off the Main Power ( Pretend the Power Supply is down)

  • Switch on the Main Power again (Pretend the Power is recovered), but the light is not on ... this demonstrates that the output is no power even the Power Failure is recovered.