I bought a 230V 1hp winch for a portable crane in my shop. I'm planning to power it by plugging it into a 30 amp welder outlet that has four prongs. There are only three wires for the winch motor.
Would leave the 4th (I assume ground) wire off and just use two hots and a common, or would you run a ground wire and attach it to the motor case or something?
The motor will only pull about 7 amps under load. I suppose I should wire a 10 or 15 amp breaker in line rather than run on the 30 amp in the circuit right now.
I'd rather run it off the welder circuit than run a new one, although I could run new. The crane moves quite a way so I can't hard wire it but rather will use the equivalent of a 12 AWG drop cord.
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The 4 prongs on the welder plug, are like this, assuming your welder is 240V and not 3 phase.
2 'hot' legs, of 120V, for a total of 240V to the welder
1 'common', which would be the neutral leg if yo wanted to go 110V
1 'ground' or as some call it the 'safety ground'.
Your 220V winch, will go into the 2 'hot' legs, and then the 'ground'. The 'common' wire, is there, (from my understanding) because some of the newer welders use computer circuits that take lower voltage, and the step-down transformer will work off of one lug of the 220, and the common. It would work just as well, using the 'ground' instead of the 'common' but electrical code requires that the 'ground' wire be there, only for safety purposes. No electricity is to go through it, under normal operation.
You'd want to wire a110V winch, to one hot wire (that would be the narrow prong on a 110V plug/socket) and one neutral wire (the wider prong) and the ground (the round one). (just in case anyone wants to do that).
I mention which wire goes to which prong, because you want to have it polarized properly. You want the power going to the switch first, and then the motor, for safety reasons. Your 220V winch, should have controls that cut the power in both wires simultaneously.
Thanks. That all makes sense. I didn't say so in my first post in order to keep it simple, but you anticipated a further use. I'm going to bring 220V to the gantry crane and on the crane I'm going to run 110V outlet and 110V light circuits. So, it's obvious I need to bring 220 4 wire to the crane so I have the common for the 110V legs as well as the ground for all circuits.
I suppose I'd better put a breaker box on the crane - a sub box. Does that sound right?
I would, even if the crane is 240V, it will take less power, so chances are you will want to run lighter wiring. You cannot have a breaker in a circuit, that is rated higher than the wiring beyond it.
You will also have to have breakers for the outlet and lights. You cannot run a 120 circuit, on a 240 breaker.
You want everything wired to code, because if you ever have a fire in your shop due to improper wiring, it can get you in trouble with your insuance company.
When I went to school, instead of studying babes, booze, and bee-bop, I studied women, wiring, and welding.
In all seriousness, in my senior year in HS, I got 3rd in the national FFA ag mechanics test, and got top individual in electrical wiring. Got a little scholarship, and used the money in Lincoln, to pass my journeyman's electrician test, and the rest of the money free-lancing other mechanics classes. Didn't quite get to full term, I stayed as long as the FFA scholarship lasted.
You'd be surprised at how many people I've run into who can't cut or weld, either.
We had one of the world's greatest shop teachers, IMO, where I went to school.
He let us do all sorts of 'challenges' for extra credit, like torch a nut off of a bolt, and leave the threads good enough to re-use. I am amazed at how few people can belive it can be done anymore, let alone do it.
I wasn't sure where I wanted to go in life, and my Dad encouraged me to learn as much as I could, to be able to fix and maintain things. He said I'd always be able to find a job, and if I did decide to go into farming, I'd be able to save a lot of money, in mechanic's fees.
Is that correct? I had to blow a lot of "mind dust" off to recall this, but see if this make sense.
My National Electric Code book is circa 1980, but in this instance I always thought the "return leg" of the circut should be the common wire. If you use the ground wire, and the female plug of the welder is physically grounded to the "plug box" that would energize the conduit itself, which could get interesting when you go to uplug something. It used to be allowed in an all metal conduit system you could use the conduit itself as the grounding system - at least it was on 110V circuts (keywords: ALL METAL CONDUIT, no gaps in continuity allowed!).
By using the common wire, you send the "used" electricity back to the power company. Ground wires are only for "accidents", not "operation".
The winch may be considered grounded through the equipment it is mounted on, or a ground could be run where the winch is installed. The welder needs a separate ground wire because it potentially could be mounted where it could not ground itself, like on rubber feet or tires.