220 electrical question

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Bigdawg90

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Maybe I’m way out of my league here, but the basic question of running a 12 amp table saw off a 50 amp breaker is fine.

There is zero re-wiring needed. A GFCI can’t run most welding rigs because welding requires grounding the circuit, but that isn’t relevant here.

Just a personal opinion but that sounds like buying a brush hog to trim a tree.

If what you’re talking about is installing a sub-panel from that 50 amp breaker to run a 50 amp and a 30 amp breaker to two different 220V outlets, that’s a good idea. You’d want a 60-100 amp sub panel loaded with a 50 amp and a 30 amp breaker.

If I’m reading it correctly thats what you want. Wiring in a sub panel from an existing 220v breaker is really easy and well within DIY. Even if you need to run new wiring it should still be easy. I don’t understand why you’d need to fab anything.

If you just want to fab it, you could just go get one from Home Depot, don’t open it and then copy its design.
 

Ahall

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Ok,

You put an old air compressor motor on your table saw, and it sounds like we are in the 2 to 3 hp range.

Best practice is a motor starter with and overload circuit and push button starter

I found this on Amazon, and its the type of thing you should be considering to protect the saws motor.
I am not saying this particular one is what you need, just that this is the type of product to think about.

1730408275081.png


The box has start and stop buttons, and inside the box is magnetic switch gear that can handle the motor current a lot better than a glorified light switch. It also has a device below the switch that can be adjusted for maximum allowable current and protect everything downstream, like your motor.

There are others available where the switch is mounted remotely from the starter, and that can be cleaner.
Just be sure the switch is easy to turn off from your normal work position and does not interfere with any controls or stock feed paths.


Now for the rest of the story - that old air compressor motor is probably a capacitor start/ capacitor run motor and not rated for continuous duty. Good chance its very inefficient to operate and may overheat if you do a lot of long rip cuts. If it has a little red reset button on the back, be sure its mounted where you can reach it. Thats the thermal overload switch - it shuts down when it gets hot. If it came out of a direct drive set up, the bearings may be undersized for a belted application. Don't go nuts on belt tension. Just enough that the blade stalls before the belt slips.
 

Ahall

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Ok, a revision. The tag on the saw motor I can only partially read. I said 17amp because I thought the tag said 34 amp at 110. But I think it's 24, so 12 amp at 220v is likely what I'm dealing with. It's a 2hp motor off a compressor so that would make more sense based on comments above re hp to amps.

My main concern here was just about what if something jammed, shorted out in the motor etc. would a breaker pop before sparks fly, if I just plugged it into the welder receptacle.
No, you will just let the smoke out of the motor, and once the smoke gets out its very hard to get it back in.
 

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