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I would like to use 2 momentary switches to controle a water pump (start stop). When you press start the pump should run until I press stop or there is a power outage. The pump should also be off when the power is back on again until I press start. What type of relay should I use and how should I wire it?

Morne
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    question has been asked a number of time. It's called a latching relay. – Marcus Müller Feb 16 '20 at 23:25
  • It has to be unlatching too without power so the latching is not using a latching relay – Tony Stewart EE75 Feb 16 '20 at 23:32
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    @MarcusMüller: I might call it a latching relay circuit, rather than just a latching relay. You need a circuit around a normal relay wired so the relay latches itself on, but drops out when the power fails. – Peter Bennett Feb 16 '20 at 23:34
  • For a motor, requiring more than 200 watts or so, the relay should have an AC motor power rating. For smaller motors, the current rating should be considerably higher than the full-load rating of the motor to safely handle starting current and disconnecting a stalled motor. –  Feb 16 '20 at 23:54
  • Does this answer your question? [Make a Latching Relay using SPDT Relays](https://electronics.stackexchange.com/questions/148296/make-a-latching-relay-using-spdt-relays) – Ariser Feb 17 '20 at 06:28

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A typical motor control switch/relay circuit:

schematic

simulate this circuit – Schematic created using CircuitLab

Peter Bennett
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