A bit of a Rubik's cube to figure out switch wiring.

Apr 05, 2023 Last reply: 3 years ago 10 Replies

I have a mill that has FWD and REV. The switch quit working and I disassembled it, that was a mistake! It is a 4 section DPDT (?) switch and has 12 compression springs, 8 moving contacts, and 4 cams. Anyway, I 'THINK' I now have I have the wiring figured out so I can reassemble the switch. Here is a diagram of the switch arrangement with jumpers and a sort of truth table, that says what wires need to be connected for what direction. Can someone confirm my diagram does what I think it does, before I go about the tedious and frustrating job of trying to reassemble the switch?

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Thanks for your time, Mikek


That wiring makes sense for a parallel motor, You have "light" and "dark" transposed in your textual descriptions vs illustrations.

Thanks for looking, I think the transposed description was only in the reverse position illustration. I have corrected it and reposted the newer version here. Does this look correct? Thanks, Mikek

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Looks good, provided you make the physical wiring match the schematic you have drawn. You can test the switch before installation. First, a different diagram:

.1..2..3..4..5..6..7..8 black topside contacts

16.15.14.13.12.11.10..9 red bottom side contacts

Each number represents a specific contact on the physical switch. Now, with the switch in the *REVERSE* position, you can use your ohm meter to ring out the switch. You should get:

1 to 16 open, 2 to 15 closed, 3 to 14 open, 4 to 13 closed 5 to 12 closed, 6 to 11 open, 7 to 10 closed, 8 to 9 open

The switch in forward will be the reverse of the above.

All of that didn't say anything different that what you drew - just another way of looking at it.

Ed

Yep, did the 3 hour job of putting all together and it doesn't pass any ohm meter testing as you suggest. I can see two contacts I installed backwards. 87.5%, I got a B, unfortunately that's not helpful in electrical wiring! I learned a lot the first assembly, the second will be a little easier. Mikek

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While all that is true, I have a replacement part on order, 4 to 7 weeks from China, only $19. However I am not the only person with this problem, if I can get mine working, the info I can provide will make it easier for others. After all this, I think the real problem is the knob has a hexagonal hole going on a hexagonal shaft, and it rotated on the shaft, it felt like a detent, but the shaft didn't rotate and the machine didn't start. Figured that out after the disassembly. Mikek

I got the switch all back together for the second time, all the proper contacts close in the position they should. I put all 10 jumpers wires on it and retested to make sure Line went where it should in forward and reverse and the same with neutral. I installed the switch back on the mill and it works correctly, FWD and REV are even correct. Thanks for the input, Mikek

Great! Thanks for posting the good result. Ed

See post #26,

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Mikek

PS, no idea what happened to bradybroussard, who started that post, tried to help him out, but no response.

Nice write up. That was some bear of a job! Ed

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