Electric Motors

Compare it to a light made for 12 volts and connect it to 24 volts (burns) connect it to a 6 volt (dim light)

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If its wired for 220 and plugged into 110 it runs really slow, theres probably a good heat buildup on it too which can lower life span.

Not sure about the other direction, probably really bad.

I know of no machine designed for 220 which will operate in 110 or any 110 which will operate on 220.That’s been my experience anyway.However a dual voltage should technically operate on both or should I say either,with a flick of a switch built underneath perhaps,or the use of a step up step down transformer.Alistair

-- excuse my typing as I have a form of parkinsons disease

It’s probably buy a new motor time.

-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †

If in doubt check your diagram or call for help.

-- Jim from Heirloom Woodshop Southern Oregon

Your right a1jim diagram will help and it is a common motor all he has to do is change the wires to what he needs.

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Question
Hi, I have a motor that is wired for 120 application, but I would like to run it on 240v. The diagram has 1 ground line 2 tape lines and one that is simply marked line. It has a specific diagram except I do not know what tape refers to. I would like to run it on a 12/3 20amp wire, but with four lines I am not sure what to do. I understand that it is hard to give an exact answer and I read your info on this exact question from the past. Please using you vast knowlege and years of experience could you give me the best most informative answer possible. I do have a clear photo of the schematic and info that could be emailed easily. I kindly thank you for your expertise and advice

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GMan is right If you hook up a motor that’s wired for 220 volts to a 110 volt source it will run very slow or not at all. If you were to leave it that way it will burn out. If you wire the motor for 110 volt service and plug it into 220 volts it will burn OUT. The addition of a transformer will work but Just change the wiring, if you can. If you add a transfromer to reduce the voltage to 110 volts from 220 volts you need to keep in mine the current that the motor is drawing so the transformer needs to be sized properly.
Like most this in life the first time is hard after that you will be giving us advice.

-- Dominic, Trinity, Florida...Lets be safe out there.

If the motor was wired for 120V and run on 240V you should be ok, assuming its all single phase power. Your motor has a power rating, lets say 3 hp (2240 watts). Since Volts x Amps = Power, if you run it on 120V you will pull about 18.5 amps, and when you run it with 240V you will pull 9.5 amps. So with that in mind, all wiring is sized based on the amount of current flowing through the wire. The larger the current, the larger the wire size needed to carry the current. So if your motor was wired for 120V (18.5 amps) and you ran it with 240V (9.5 amps) you should be safe from any overheating or fire hazard. HOWEVER, if you did the other way…...I hope you have a fire extinguisher! Hope this helps.

-- J. KUGEL Kirkland, WA

Answer
Mike: With the “EXPERT” site I cant send drawing of any kind. Usually with motors that are dual voltage type there will be a wire connection that has to change, or a plug that you move from one pin to another. The main difference is when the motor is set up for 120volt operation you are using the following::

1 hot, 1 neutral, and 1 ground.
for 240 volt operation you use the following::
2 hots, 1 ground, neutral (white wire) is caped off.

I would get the information as to make, model, hp, off the motor and then check for the manufactors web site to try and get a wiring diagram off of it. Hope that helps….

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Kugel it will run on 220 but it will have half the hp that it shold have.

-- --<<<<<< I will not stop until I get it right. >>>>>>--

GMman, I was talking strictly from a safety/fire hazard standpoint, not performance charateristics.

-- J. KUGEL Kirkland, WA

Yes safety is always first but the only thing that would burn would be the motor it would go dead.

-- --<<<<<< I will not stop until I get it right. >>>>>>--

I have burn motors before and you don’t get a fire.

-- --<<<<<< I will not stop until I get it right. >>>>>>--

Good for you GMman, im glad you have never had to deal with an electrical fire. However, for you to say there is no risk of fire when a motor is burning up is just plain wrong. The NEC was produced for a reason….

-- J. KUGEL Kirkland, WA

Motors that can be wired for 110/220 essentially split the windings in half. To run on 110V, both windings are run in parallel. To run on 220V, the windings are run in series. This may help figure out how to change the wiring on your motor.

If wired for 220V and run on 110V, the motor will run slowly (if at all, it may just hum) and heat will build up. If you notice right away and turn it off, no damage will result.

If wired for 110V and run on 220V, the motor will spin at the right speed but draw way too much current. If the motor is fused (or CB, whatever) for the correct current at 220V, the circuit will open and, again, no damage. That’s what fuses and CBs are for.

There is a third condition where the windings are connected properly in series or parallel, but wired antiphase (the two windings are out of phase with each other). In the case, the shaft will not move, the motor will hum loudly and probably blow any fuse or CB it is connected to. Still probably no damage (I haven’t managed to misconnect any motor this way myself – yet!).

Motors are pretty rugged. It usually takes quite a while of running in a bad condition to destroy them. I have personally run motors in both the wrong conditions while working out motor wiring and managed to figure it out without burning up the motor.

-- "Find out what you cannot do and then go do it!"

Find a local electric motor service and repair shop. Tell them exactly what you want and how it’s to be used and buy a nice old motor from them. Electric motors are tremendous value workhorses and are relatively inexpensive. You won’t find a better bargain.

—Peter

Also very important that no matter what voltage you run the motor at it will always develop the same HP value.
Simplifying to extreme P=V x I where P = power in Watts, V = Voltage and I = Current

At ac conditions other parameters apply but to figure out what is happening it is a rough approximation.

When V doubles since P IS constant I is halved.
That is the biggest advantage of running motors at 220V the currents is half the value at 110 therefore you can use a thinner extension and the breaker also can be made smaller.

Another crucial difference between USA and Europe is that here 220V is actually 208V the reason is that here we run 2 Hot wires essentially 2 110V but in reality they are around 117Vac but they are not 180 deg out of phase in fact they are 120deg out of phase and that determines that the actual voltage across the 2 hot wires is 208V

In Europe they have 1 hot 1 neutral and 1 ground. In continental Europe is 220Vac while Great Britain is 240Vac.
The other big difference of course is that over there they run 50Hz the theory was less frequency less chance of killing you if you get whacked. In the US every body knows the mains runs at 60Hz

The net result is that if you have a motor or coil rated at 220V 50 Hz and try and run it at 208V 60Hz becauise the higher duty cycle imposed to it when running here will result in eventually burning the motor or coil (been there, done that by the way) instead running a motor that was designed for 60Hz it will run just fine when running over there at 50Hz.

And by the way a motor that is wired for 220V will turn very slowly if at all when you power it with 110V.
Now if you apply 220V to a motor wired for 110V since the resistance of the winding is half what it should be the current rushing will be double the normal start up current. Unless you wired grossly incorrectly your panel the breaker should trip immediately….
Probably your motor will be saved by this, I would check the windings with an Ohm Meter (Tester) and verify that it did not Open or short circuit to ground….

Hope this helps you. Take care.

nowhereman, assuming you have a motor and don’t know which way it is wired, look inside the connection box and see if there is a diagram.

If you have a motor wired for 240 and connected to 120, it will probably just hum and start getting hot, trip the overloads (not to be confused with fuses or circuit breakers) if any. It will eventually burn up if just left, it may blow the fuses or trip the circuit breaker before or after it is damaged.

If it is wired for 120 and connected to 220, there is a good chance it will burn up immediately. There are very few devices that can take a double dose of voltage. Lots of theory stated above above, but in reality, you don’t double the voltage without paying a price.

Remember the important part of operating electrical equipment is to keep the smoke in! If the smoke gets out, very few electrical devices will work without the smoke:-))

-- Debt is nothing more than the 21st Century's form of slavery.