Yamaha EF6300iSDE generator and starting A/C on 240 volt

belfert · August 03, 2013, 02:30:24 PM

I have a Yamaha EF6300iSDE inverter generator I am playing with. I have 50 amp service in my bus. When I plug into the 120/240 outlet none of my three rooftop A/C units will start. The generator will show 50% on the power graph and the overload light comes on. Now, if I plug into the 30 amp 120 volt outlet with a 30 amp to 50 amp converter I can start any of the A/C units. In fact, I can run three rooftops on the 30 amp plug with the compressor running on all three.

Why would the rooftops not work when in 240 volt mode with a 50 amp connection? Is 26 amps on one leg just not enough to start a rooftop even when it is 75 degrees outside? It might be a moot point if I can run everything I would like on the 30 amp 120 volt outlet.

I just figured I couldn't take advantage of all 5,500 watts without using the 240 volt connection.

To clarify, the generator has both a 120/240 volt 30 amp outlet and a 120 volt 30 amp outlet.

robertglines1 · August 03, 2013, 03:46:43 PM

Just a thought but when you go to 220 and split are you just getting two 15 amp legs= 30 amp at 220. showing 50% load 15 amps would be very little to start even one ac in allot of cases. I did not say run. I said start. I know there has been problems with inverter gen sets running inverter type Air Conditioners. Just throwing it out there. Do not know engineering reason. Bob

belfert · August 03, 2013, 03:54:09 PM

It actually produces 26 amps on each leg at 240 volt. I suspect 26 amps just isn't enough to start a 15K BTU compressor. (Yes, I had economy mode turned off.)

I guess the real question is how to utilize all 5,500 watts if I can only use the 120 volt 30 amp receptacle? The strange thing is I can run all three of my rooftops on the 30 amp connection and I know they pull more than 30 amps combined with the compressors all running.

robertglines1 · August 03, 2013, 05:34:43 PM

So it changes to a 6300 watt gen set? continuous? Just a observation. It's frustrating what they advertise they will do and what they deliver. I usually figure about 75% of what they advertise is more like reality. Bob

belfert · August 03, 2013, 08:00:56 PM

5,500 watts is the continuous output and 6,300 watts is the maximum output.

Lin · August 03, 2013, 08:56:26 PM

If you plug the 50 amp plug into 50 amp/240v shore power does everything work correctly?

Dirtball · August 08, 2013, 07:04:49 PM

Check your homemade plugs .... just a thought , I've wired a plug wrong in the past.

belfert · August 08, 2013, 08:27:00 PM

Nothing is homemade. I bought Camco twistlock to RV adapters specifically designed to work with generators. I'm pretty sure at this point the issue is there simply simply isn't enough amps on either leg at 240 volt to start a 15,000 BTU air conditioner.

bevans6 · August 09, 2013, 04:31:17 AM

got it wrong.

belfert · August 09, 2013, 05:00:17 AM

240 volt is two 120 volt legs so each 120 volt leg should be 26.3 amps surge. Regardless it isn't enough to start a 15,000 BTU A/C.

paul102a3 · August 09, 2013, 06:12:26 AM

Just took a quick look at the control panel of your genset. I have a kubota genset I use for home backup power and your unit and mine have very similar outlets and switches.

This drove me nuts at first but on mine, the 120/240 volt switch must be in the 120 volt mode to get full voltage and amperage from the 240 volt, 4 wire outlet. It makes no sense but that is the way mine works and it might be same on yours.

In my owners literature, they name the 120/240 toggle switch full/half power switch.

Paul