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Please help me

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stustu92

New Member
in a car, i want to supply a solenoid with a 2 position rocker switch, but i only want the soleniod to have a supply if the switch is closed after the ignition is turned on. if the switch is closed before the ignition is turned on, then i don't want the solenoid to have a supply. I'm trying to do this using relays, but haven't been successful so far. Any ideas would be much appreciated.

Thanks :)
 

Symon

New Member
Have the relay coil energised off the ignition switch. Then have the rocker switch in series with a set of normally open contacts on the relay and then to your solenoid.

That way, if the ignition is off, no voltage is present at the rocker switch, so the solenoid cannot energise. When the ignition is on, the relay is energised, allowing voltage to be present at the rocker switch.
 

dingo

New Member
Just to clarify.

Ignition off – no power to switch
Ignition on – no power to switch if switch was in the on position (ever?)
Ignition on - power to switch if it was off when ignition was first turned on.

Is that what you had in mind?
 

stustu92

New Member
Just to clarify.

Ignition off – no power to switch
Ignition on – no power to switch if switch was in the on position (ever?)
Ignition on - power to switch if it was off when ignition was first turned on.

Is that what you had in mind?
Yeah that is correct.
 

dingo

New Member
You could do this with
2 x SP Relay
1 x DP Switch

RLY 1 & 2 C - IGN
RLY 1 NO - RLY 1 coil a
RLY 2 NO - RLY 2 coil a
RLY 1 NC - RLY 2 coil a
RLY 2 NC - RLY 1 coil a
SW (1) C - IGN
SW (1) NO - RLY 1 coil a
SW (1) NC - RLY 2 coil a
SW (2) C - RLY 2 coil a
SW (2) NO - Solenoid
RLY 1 & 2 coil b - GND


*SW (2) indicates second pole of switch, IGN = Ignition V+



This will latch one relay that will disable the other relay when the ignition is switched on depending on the position of the switch. Power is taken from the relay that latches on the switches NC position to power the solenoid. To reset turn off the ignition.

If you want an electronic version of this let me know.
 

Phasor

Member
dingo, I have just simulated your relay circuit, and it does not appear to function as intended.
 

dingo

New Member
Phasor said:
dingo, I have just simulated your relay circuit, and it does not appear to function as intended.

Opps :oops:
Phasor you are right, my mistake it looks a lot different when you draw it, even in paint.

Have used a second set of contacts for the relays, hopefully this should work better than the first try.



 
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