wiring electric motors for hobby


Old 03-17-15, 11:59 AM
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Location: USA
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wiring electric motors for hobby

I am building a tool to polish rocks that uses three ac motors and an on/off switch and I need help understanding how these will need to be wired.

I have three surplus AC gear motors that have two wires on them. These motors are mounted independently in a wooden framework. I need to know how to wire these motors to a switch and a grounded plug so that I can plug into a ground fault outlet because the polishing process involves the use of water.

I assume the motors should be wired in parallel and the switch in series but what about the ground? does that need to go to each motor since this has a wooden frame, and if so is the ground in series?

I an NOT an electrician so I hope my questions make sense. If more information is necessary let me know.
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Old 03-17-15, 06:16 PM
Join Date: Nov 2007
Location: MI
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You're leaving US to assume a lot...
So if you're planning 3 separate direct-drive tumbler drums, each driven by the slow RPM of a gear motor, then yes you can wire all 3 in parallel with a switch in series to the GFI receptacle.

Without the physical separation of a belt or rollers how can you be sure you won't spill water into a motor? You might need to shield them with a baffle--one that doesn't restrict air flow.
Old 03-18-15, 07:37 AM
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This project is a rock sphere polisher. Basically the stone to be ground and polished is cradled in sockets on the ends of extended shafts of the motors. There may be a slow drip of water to help lubricate the stone but it would be uncommon for the motors to get wet but of course it is possible. It is something like this https://www.youtube.com/watch?v=ubqclAv2Zts

How should the grounds from each motor be connected series? parallel? doesn't matter?
Old 03-18-15, 07:46 AM
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The grounds should all be connected together, which technically means they are in parallel, but that doesn't mean you have to wire it like a "star" with each motor having a separate ground wire back to a central point. You can use a single ground wire from motor to motor and then back to the junction box where the power cords are spliced. Either method is acceptable.
Old 03-18-15, 09:18 AM
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You mentioned your motors only have two wires. Do you have a place to attach a ground to the motor housings?
Old 03-18-15, 01:11 PM
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You are correct, there is not really a place designed for that. There are screws that hold the gear box together so that might be an option.

I am open to any suggestions but it is a pretty bare motor, the only mounting screws are to attach the gear box to the wooden frame.

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