240v from generator

[Fifthwheel10]

Background: I am a commercial/industrial electrician, 21 yrs experience. I understand electricity but may not convey so that the unknowing will understand what I am explaining.

Problem: my generator, Onan qc 5500 puts out 120/120. Both legs out of the generator are the same phase, testing 0v from wire to wire, not 240v. There are two 30a breakers on the generator, not tied together. I thought that odd at first but now I understand this generator will not support 240v as is. If it was able to support 240v the breakers would have been tied together.

Now, knowing that, and having a 240v mini split already installed I can only use the mini split from shore power and not the generator, or can I? I guess my main question is, how can I get 240v out of a 120/120 generator? Is there a phase shifter that can handle a generator? Yes, this is my first time seeing a 2 pole generator. I assumed it would be able to output 240v.

Thanks in advance.

[Mallie]

Yes, it is easy to step AC up or down. Just look on Ebay.
https://www.zoro.com/square-d-transf...MaAnNnEALw_wcB

Course it is going to take twice the 240v amps from the 120v. If it is an inverter driven unit, should not be a surge on start.

[twinboat]

Check the exact model #. It seems that some can be configured for 240 volts.

Problem is, you will only get 23 amps per leg, but with a 240 volt AC, it may be OK.

My 1999 Generac was able to be converted. The wiring diagram showed how.

[Old Scout]

…..curious--true, 240v, phased power on two legs is rarely required in RV industry applications--what issue are you needing to solve by converting your generator to 240v, phased power?

[Sweetbriar]

There are transformers that will produce 220 VAC split phase from a single phase 120 VAC input but as Mallie posted you'll need twice the amps. Might be easier to return the current mini split for a single phase model if possible.

[Mr_D]

The 10 and 12.5K Onan Quiet Diesel liquid cooled gen will produce 220/240 without modification. But they weigh close to 800#'s too.
My dryer is a 220/240 volt unit with the QD 12.5k gen

[Soppy]

Some of the generators can be rewired to 240 volt and some can't . You could get a 120 to 240 volt transformer and connect it directly to the mini split using your original 120volt breaker. That way there would be no modifications to the coach wiring and the A/C unit will work from genny and shore power.

[twinboat]

Originally Posted by Old Scout

…..curious--true, 240v, phased power on two legs is rarely required in RV industry applications--what issue are you needing to solve by converting your generator to 240v, phased power?

He installed a 240 volt mini-split AC unit.

[mobilemike]

I have a generator with a built in 240 outlet and two 120v receptacles.

[glennwest]

Originally Posted by Sweetbriar

There are transformers that will produce 220 VAC split phase from a single phase 120 VAC input but as Mallie posted you'll need twice the amps. Might be easier to return the current mini split for a single phase model if possible.

All the 110v mini splits are max of 12k output. Any more than that you need 220. One 12k mini split heats my entire Teton with the help of the fireplace. Now it needs help to cool this. I'm going 220 also for more output.

[clifford j]

I need some help from those with knowledge of generators. Question I have is ,,, does a 120/120 output have two seperate neuteral legs. And, can the two neuteral legs be bridged to produce 240 volts. If so the breakers must be mechanically be bridged with a pin or clip. Just asking

CLIFFORD

[Fifthwheel10]

Originally Posted by Soppy

Some of the generators can be rewired to 240 volt and some can't . You could get a 120 to 240 volt transformer and connect it directly to the mini split using your original 120volt breaker. That way there would be no modifications to the coach wiring and the A/C unit will work from genny and shore power.

Thank you soppy. This seems like the most sensible idea, hopefully temporary, as I am going to email the manufacturer to find out if a tap or two can be changed. I do know that the breaker handles will have to be tied together. Lol, just thought of more that would have to change if I changed tap, the nameplate sticker from single phase 120 to single phase 120/240. Not sure how the neutrals are configured, but I will look into that also if taps are changed.

Thanks again!

[mhudson]

Onan makes a small 5500 gas commercial generator with the same footprint as the RV style. It is a 120/240 generator. (Has a white case)Most of the green RV models cannot be reconfigured to 240.

[Soppy]

Originally Posted by Fifthwheel10

Thank you soppy. This seems like the most sensible idea, hopefully temporary, as I am going to email the manufacturer to find out if a tap or two can be changed. I do know that the breaker handles will have to be tied together. Lol, just thought of more that would have to change if I changed tap, the nameplate sticker from single phase 120 to single phase 120/240. Not sure how the neutrals are configured, but I will look into that also if taps are changed.

Thanks again!

Some generators have 2 separate windings connected in parallel to produce 120 volts. You will nave 2 neutrals and 2 hots. For 240 volts the windings are connected in series (one hot to one neutral) This connection will now be the new neutral . The voltage regulator will have to be changed for 240 volt operation. I have seen some just use a 120 volt regulator on a 240 volt generator . You will need the proper wiring diagram before you start, otherwise you could "smoke" the generator.

With a 240 volt generator , you may have a problem with appliances being on the same leg and overloading on side of the generator.
If you use a transformer , it will be rite at the mini-split and no changes to the coach wiring or breakers will have to be made.