Reverse an AC motor?

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Ropata

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#244992 13-Jan-2019 12:20

I've just finished refurbishing and old drill press but the motor is running the wrong way. The go ogling I've done is just making me more confused. I usually have this problem with 3 Phase motors but that's an easy fix and I've never had to do this with a single phase. Any ideas? I can take some ohms readings if it helps.

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#2160103 13-Jan-2019 12:30

Is the capacitor connected connected the wrong way round maybe?

Ropata

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#2160108 13-Jan-2019 12:33

Yeah I was reading a bit about that. I may try that if no one else can see anything obvious.

Ropata

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#2160119 13-Jan-2019 12:46

Capacitor made no difference.

Ge0rge

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#2160122 13-Jan-2019 13:03

You need to swap the wires going to the start windings, not the cap.

Ropata

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#2160392 13-Jan-2019 17:39

Cheers. How can I identify them with a multi-meter? Higher ohms?

Ropata

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#2160395 13-Jan-2019 17:43

here are 6 wires coming out to the terminal block. Black, red blue and 3 white.

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Ropata

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#2160415 13-Jan-2019 18:26

https://youtu.be/QKYeXGaulOI

sparkz25

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#2160521 13-Jan-2019 20:10

are you able to dissconnect the phase and neutral and send a pic of the rest of the wiring underneath the terminal block?

where are you located?

Ropata

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#2160544 13-Jan-2019 20:27

I'm in Newlands Wellington. There are no wires under the block, they all come from the motor housing beside it. There are 3 white wires and black, red, blue. All the videos I'm finding only have 3 wires.

sparkz25

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#2160549 13-Jan-2019 20:32

was going to say if you are in the waikato i could sort it for you

there looks like there is a wire hidden under the block highlighted and circled, where does that wire go?

Ge0rge

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#2160570 13-Jan-2019 20:49

Hard to say without having a tinker myself. The 0.2ohm readings I would suggest are a straight short - ie you'd get the same reading if you touched the probes together.

It's also reasonably hard to determine the readings while still in circuit, and you're a brave man metering a cap!

I want to say just swap the blue and red wire, and see what happens, however that's reasonably irresponsible advice when I haven't actually been able to trace the circuit fully myself. On the other hand, it'll either reverse, or pop the fuse ;)

Nicely equipped shop in the background by the way.

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sparkz25

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#2160578 13-Jan-2019 21:01

Ge0rge: Hard to say without having a tinker myself. The 0.2ohm readings I would suggest are a straight short - ie you'd get the same reading if you touched the probes together.

It's also reasonably hard to determine the readings while still in circuit, and you're a brave man metering a cap!

I want to say just swap the blue and red wire, and see what happens, however that's reasonably irresponsible advice when I haven't actually been able to trace the circuit fully myself. On the other hand, it'll either reverse, or pop the fuse ;)

Nicely equipped shop in the background by the way.

the 0.2ohm reading im picking is the CF switch which is inline with the cap

Ropata

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#2160583 13-Jan-2019 21:13

Ge0rge: Hard to say without having a tinker myself. The 0.2ohm readings I would suggest are a straight short - ie you'd get the same reading if you touched the probes together.

It's also reasonably hard to determine the readings while still in circuit, and you're a brave man metering a cap!

I want to say just swap the blue and red wire, and see what happens, however that's reasonably irresponsible advice when I haven't actually been able to trace the circuit fully myself. On the other hand, it'll either reverse, or pop the fuse ;)

Nicely equipped shop in the backgrouncd by the way.

Thanks George. It was definitely unplugged and I always short the caps after that time I was playing with a microwave transformer lol.

I might take some time and disconnect it all and take some clean readings.

My shop has a lot of capability. It's electrical knowledge that's lacking.

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#2160623 13-Jan-2019 21:39

Tagging @themantis, general genius at this sort of thing.

TheMantis

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#2160680 13-Jan-2019 22:33

Swap over the connections to either the start or run winding. Just one, not both, doesn’t matter which. This can be done using the brass strips if you want, it’s what they’re for.

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