Discuss 12v dc motor forward reverse off switch in the UK Electrical Forum area at ElectriciansForums.net

suffolkspark

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Hi all, had a job with a swimming pool bubble cover that rolls onto a spool with a small 12v dc motor, it had a reverse key switch to roll and unroll the cover which has had a load of water in and got corroded and stopped working. Thought I'd taken a picture of the switch when there but I havnt ?‍♂️ anybody able to point me to a suitable one? It had 8 terminals would like a ip rated surface mount one 4inch x 6 inch ish if poss, as this one just mounted in a supporting column of the spool which hasnt done it any favours
 
Depending on how much depth you have and other factors, is it possible to make your own switch from something like 3 position spring return to centre switch and add the contacts you require to the back?
Something like the below switch.

1586254197418.png
 
That's along the lines of what's there now except with a key and its spring returns to centre, I'm not sure what switches I'd need for it not done dc motor reversal before, wish I'd got a picture :(
 
There are two configurations.

The 'basic' way needs a double-pole changeover with the fixed contacts of the two poles strapped in an X. If you call motor leads A & B, in one direction make A +ve and B -ve. Other direction A -ve and B +ve. With a centre-off position, the switch essentially consists of four normally-open contacts, two of which close in each direction.

Some types of switch leave both motor leads connected to -ve at rest, then switch one lead over to +ve for one direction and the other likewise. This allows control from multiple positions as the switch never breaks the circuit. It also provides (for a normal permanent-magnet motor) more rapid stopping when the control is released. A PM motor generates a voltage as it spins down, and having its leads linked (by both being connected to -ve) creates a circulating current that brakes it to a halt. Useful to avoid overrunning endstops etc and helps avoid the load inching the motor around if there's no mechanical brake.

Either setup could be arranged with a modular switch. What is most important obviously is that the N/O and N/C contacts never overlap (i.e. it's reliably break-before-make) otherwise they will short the supply.
 
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That's along the lines of what's there now except with a key and its spring returns to centre, I'm not sure what switches I'd need for it not done dc motor reversal before, wish I'd got a picture :(

Well if it's just the switch that has corroded contacts then you just need to replace the switch. Or have I miss-read something?
 
Yea I could probably keep the key section but didnt catch the brand of it either so not sure if different switch modules fit the back of it, think I'm gonna pop back there and remove it and bring it away with me, cheers for info lucien I think its making more sense now, I've also seen basic 3 position toggle switches that do it and can see the X in the connections on them so I sort of now know what I'm trying to achieve!
 

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