220V Motor Wiring

[Bob Hoffmann]

I have a motor that can run on either 110 or 220. If I plug it into 110 it runs (it is a dust collector motor). I want to switch it to 220V because the draw (amp) is too high for the 20 amp 110 volt circuit.

I looked at the wiring diagram, and it looks like it is set for 220V. But it runs when I plug it into 110V. Is that possible -- that a motor that is wired for 220v will run if it is plugged into 110V?

If I plug it into 220V will I smoke to motor?

For background, it is a Reliant dust collector with a 2 HP motor. The wiring is for 1 and 4 to load, and 2 and 3 together -- which is what it is set for -- and that is for 220V. For 110V it says to tie 1 & 3 together and put t load, and 2 & 4 together and to load.

[Julie Moriarty]

The circuit and the motor wiring must match. If it's a 240V, 2-pole circuit, the motor must be wired for 240V. If you plug a 120V motor into a 240V circuit and turn it on, it will run high for a few seconds and then start smoking until it burns out.

It looks like you have two choices, either install a 30A 120V circuit or a 15-20A 240V circuit. More information would be needed to know exactly what to do.

[Jeff Ramsey]

If the plugs and receptacles are correct, you won't be able to plug a 220V plug into a 110V receptacle, and vice versa.

See the diagrams here:

http://www.generalcable.com/NR/rdonl...NEMA_Chart.pdf

[Myk Rian]

Get an electrician. Especially if you have no idea what you are doing.

[Bob Hoffmann]

I purchased this unit used, and decided to believe the motor wiring diagram instead of the plug that was on the machine. So I switched out the plug, and plugged the unit into a 220V outlet.

Being cautious, I did a quick on / off to see what happened, then let it run for a while when nothing smoked on the first try. And guess what -- it works fine at 220V. It seems as though the previous owner had a 110 plug and used it with 110 while the unit was wired for 220V! What a difference the performance makes when it is running at the right voltage!

Running it at 110, the performance was OK, but definitely not the gain that I thought that I was going to get beyond what I was using (which is one of those portable units that has a universal motor and says that it pulls 910 cfm). Running it at 220 and I see what a dust collector should be like -- what a difference!

Hard to believe that the previous owner was using it with the wrong voltage all along! His loss and my gain. I guess the lesson is to believe the diagram, and not the guy selling it.

[jack duren]

Get an electrician. Especially if you have no idea what you are doing.

Most electricians won't know.

[Robert Engel]

Sounds like he wired a 110 outlet for 220 and used a 110 plug.

[Frank Pratt]

The circuit and the motor wiring must match. If it's a 240V, 2-pole circuit, the motor must be wired for 240V. If you plug a 120V motor into a 240V circuit and turn it on, it will run high for a few seconds and then start smoking until it burns out.

The results of running a 240V motor on 120V can vary. Under no or low load, the motor will come up to full speed (slowly) & sound like it's running normally. As soon as load is applied it will quickly slow down & the start winding will re-engage. The motor will soon burn out or trip the overload. Even running at no load the motor won't last long.

An electric induction motor will try to run at it's rated power. If the voltage is lowered, it will draw higher current in an attempt to compensate. And it's that high current that burns out things.

[Larry Gipson]

You will have to completely rewire the motor to safely use something wired for 110v on 220v. Most of these have 2 sets of coils. They may be in parallel for 110v and in series for 220v. Put an ohmmeter on it and write down the low and high resistance. Use the higher one You may be able to find the wiring info for the particular motor. When in doubt, read the directions. I usually get around to that too late

Make sure you use the proper plug or you'll burn something up for sure. I use the 15A 220v plug in the shop. It looks sorta like a 110V plug with the flat contacts turned sideways.

[Julie Moriarty]

I purchased this unit used, and decided to believe the motor wiring diagram instead of the plug that was on the machine. So I switched out the plug, and plugged the unit into a 220V outlet.

Being cautious, I did a quick on / off to see what happened, then let it run for a while when nothing smoked on the first try. And guess what -- it works fine at 220V. It seems as though the previous owner had a 110 plug and used it with 110 while the unit was wired for 220V! What a difference the performance makes when it is running at the right voltage!

Running it at 110, the performance was OK, but definitely not the gain that I thought that I was going to get beyond what I was using (which is one of those portable units that has a universal motor and says that it pulls 910 cfm). Running it at 220 and I see what a dust collector should be like -- what a difference!

Hard to believe that the previous owner was using it with the wrong voltage all along! His loss and my gain. I guess the lesson is to believe the diagram, and not the guy selling it.

Switching out a cord end happens all the time. I've asked people why they just didn't buy the right cord end and receptacle. "I already had the other stuff" is all it boiled down to. They didn't want to spend the money. It sounds like the previous owner got the motor from the guy who switched the cord end or (shakes head) ran the motor off 120V and didn't know the difference.

Glad to hear everything worked out for you.

[John Lifer]

Sounds like he wired a 110 outlet for 220 and used a 110 plug.

This is what happened, otherwise there wouldn't be any performance.

[Wade Lippman]

For background, it is a Reliant dust collector with a 2 HP motor. The wiring is for 1 and 4 to load, and 2 and 3 together -- which is what it is set for -- and that is for 220V. For 110V it says to tie 1 & 3 together and put t load, and 2 & 4 together and to load.

Some are more complicated, but what you describe is true when there are only 4 wires; the windings are in series for 240v and parallel for 120v.
I would have bet it would be damaged by running it as you got it on 120v, but I guess not.