Can I run a 220v appliance off a 120v generator?

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Old 04-21-06, 07:39 PM
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Can I run a 220v appliance off a 120v generator?

I live in Central America. Because of frequent power outages, I have a 3000w Honda Generator and a transfer switch to power my house. This works well for everything in the house, except for our 220v split air conditioner.

I'm wondering if anyone knows of a solution to running a 220v appliance from a 120v generator. I know there are step-up transformers, but I'm not sure how I would wire that into the 220v connection of the air conditioner, since it runs on 2 110-120v lines.

Any help would be appreciated.
 
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Old 04-21-06, 07:48 PM
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No. The air conditioner will probably pull too much power. There is probably a 240 volt outlet on the side of the generator. If not, then it wasn't meant to handle large appliances like that. You may have to increase the wattage of the generator (one that will handle 240 volts) or move air with alot of fans.
 
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Old 04-21-06, 07:57 PM
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I mentioned that it was a "split" air conditioner to highlight the fact that it's very efficient. It's rated at only 2,000 watts, so the generator does have enough power to run it. I'm just looking for advice on stepping up from 120v to 220v and dividing it on 2 lines.
 
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Old 04-21-06, 08:30 PM
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You need a 1:2 3000VA step-up transformer.
Google gave some results that appear promising such as Transformer 3000 VA, 110 V / 230 V.
 
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Old 04-21-06, 08:43 PM
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Thank you very much.
 
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Old 04-22-06, 09:02 AM
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Which Honda Generator do you have? The 3000 Watt honda inverter generator can be run in parrallel with an identical set to produce 240 volt power. It may also be possible to have the wiring of the generator changed so it produces 240 volts in addition to 120 volts.
 
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Old 04-22-06, 06:27 PM
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So if I understand, the air conditioner consumes 2'000 watts at 240 volts and the generator is 3'000 watts at 120 volts. A transformer could handle the voltage conversion but it looks like your generator is too small. You would need at least a 4'000 watt (at 120 volts) generator and probably a 5'000 watt to account for the loss through the transformer and to help start the airconditioner.
 
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Old 04-22-06, 06:51 PM
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Originally Posted by Pilot Dane
So if I understand, the air conditioner consumes 2'000 watts at 240 volts and the generator is 3'000 watts at 120 volts. A transformer could handle the voltage conversion but it looks like your generator is too small. You would need at least a 4'000 watt (at 120 volts) generator and probably a 5'000 watt to account for the loss through the transformer and to help start the airconditioner.
You do not understand correctly.

A watt is a watt. The generator produces 3000 watts. If you could convert this to 240 volts, it would still be 3000 watts. The current would change.
 
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Old 04-22-06, 07:13 PM
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Oops. I was thinking amps but typing watts.
 
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Old 04-22-06, 11:38 PM
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If the a/c unit draws 8A @ 250V, it will draw 16A @ 125V.

Transformer losses might be 2%, but nowhere near 50%.

The a/c unit might require 50A to start the compressor. So a larger transformer will handle that better than a smaller transformer. However, there is really no point in having a transformer rated a lot higher than the alternator. Such would be extra expense and weight without producing any additional output.
 
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