I have a Yamaha EF6300iSDE inverter generator. I have 50 amp service in my RV. 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?

Someone will be along shortly with a better comment, but the short version is - - - your camper does not run on 240v. The 50amp connection for the camper is two 120v legs. Everything on AC circuits is 120v.Hope all is well and no damage done.

Hopefully you didn't damage anything. Does your owner's manual discuss the usage of its 240v outlet?

Yes, I understand that a 50 amp connection is two 120 volt legs. The generator has a L14-30 receptacle so it has two hots, a neutral, and a ground. I am using a proper adapter to go from a L14-30 receptacle to a 50 amp RV receptacle. I was NOT running 240 volts into appliances designed for 120 volt. The issue appears to be that when a compressor starts it pulls too much juice.My real question I guess is how do I get all 5,500 watts out of the generator considering it won't start air conditioners using the 120/240 volt receptacle? There is a 120 volt 30 amp receptacle, but that is only rated for 3,600 watts. I have used the 30 amp receptacle and everything works fine.

Sweet Old Bill wrote:Someone will be along shortly with a better comment, but the short version is - - - your camper does not run on 240v. The 50amp connection for the camper is two 120v legs. Everything on AC circuits is 120v.Hope all is well and no damage done.A properly designed 50 amp RV connection should be 240 volts across the two hots! Technically, you could supply each side of the outlet from the same 120 volt feed as most RVs don't have 240 volt appliances, but what happens when someone has a 240 volt appliance and expects 240 volt? I believe it would be a code violation to wire a 50 amp receptacle and not have it be 240 volt with a ground and a neutral.Now, a 30 amp RV connection should NEVER be 240 volt. Plenty of electricians have wired them at 240 volt and fried the electrical stuff in the RV.As already stated, I was NOT running 240 volt into 110 volt appliances.

I see your point exactly. It almost seems that either leg is limited to 26 Amps in the 50A setup, but you can get 30 amps out of one leg only without overloading the generator.I don't know whether if will make any difference or not, but you could try running the A/C units to give them a little prestart on the 30A plug then do a quick switch on your cable and a quick start on your A/C units and plug into the 50A setup.You could also try shutting down the feed to everything else except your a/c's so you are not using any power for your converter, fridge (on auto) or other load grabbers and see if that makes a difference.

Why won't Yamaha EF6300iSDE generator start A/C on 240 volt?

Learjet
Explorer
Aug 07, 2013
belfert wrote:
I got one heck of a deal on this generator from Craigslist. I paid $1,800 which is less than a new 3,000 watt model. So far, the generator works just like new. The seller claimed he was buying an RV with a built-in generator.

I can power pretty much everything I want to through the 30 amp 120 volt receptacle since it allows me to pull way more than 30 amps. The question is if it is really safe to pull 35 to 40 amps through a 30 amp receptacle? My shore power cord is 6 AWG because it is a 50 amp cord, but I have to use two adapters at the generator end.

It wouldn't make sense to buy a different generator. I'll just have to accept the fact that I may not be able to use all 5,500 watts. I still have more usable watts than an EU3000 or EF3000.

What about using on of those 50 amp adapter that has 2 plugs? One to the 30 amp and one to the 20 amp rec.
belfert
Explorer
Aug 07, 2013
I got one heck of a deal on this generator from Craigslist. I paid $1,800 which is less than a new 3,000 watt model. So far, the generator works just like new. The seller claimed he was buying an RV with a built-in generator.

I can power pretty much everything I want to through the 30 amp 120 volt receptacle since it allows me to pull way more than 30 amps. The question is if it is really safe to pull 35 to 40 amps through a 30 amp receptacle? My shore power cord is 6 AWG because it is a 50 amp cord, but I have to use two adapters at the generator end.

It wouldn't make sense to buy a different generator. I'll just have to accept the fact that I may not be able to use all 5,500 watts. I still have more usable watts than an EU3000 or EF3000.
Specularius
Explorer
Aug 05, 2013
Gdetrailer wrote:

SPECS HERE

"45.8 amps /52.5 amps @120V; 22.9 amps/26.3 amps @ 240V"

By the way, the 22.9A is 2748W and surge 26.3A is 3156W at 120V which IS what you are getting to EACH 120V "leg".

I think Gdetrailer has your answer...you can get 45.8 amps connected to the 30A 120V outlet.
bigcitypopo
Explorer
Aug 05, 2013
If you are looking for cleaner power, you could wire in a line conditioner after the breaker and have it feed the circuit you want. ? then it doesnt matter what power source you have. It'll offer surge protection to your sensitive stuff.
Gdetrailer
Explorer III
Aug 05, 2013
belfert wrote:
Gdetrailer wrote:
belfert wrote:
dougrainer wrote:
Do you have 120 volts ANYWHERE in the RV when connected to that 50 amps? The AC units(compressor) has NO WAY to know what the supply is. Do the AC fans run? Do the compressors try to start? Doug

Yes, I have 120 volts to everything in the RV when plugged into the L14-30 outlet on the generator. The fans on the A/C units will run. The compressors just won't start on any of the A/C units.

I understand the 26 amps is surge only, but the compressor start-up is just a short term surge and after start-up it should only draw 12 to 13 amps.

I managed to run all three of my A/Cs and the 1500 watt water heater at the same time through the 120 volt 30 amp connection. I had to be pulling over 40 amps, but I didn't get out my clamp-on amp meter to check. I only ran the water heater for a minute or two.

Running high surge equipment on 30A shore power means nothing... Basically shore power is "unlimited" when it comes to surge currents, generators not so much.

I wasn't running on shore power when I was using 120 volt 30 amp connection. This generator has both a 30 amp 120 volt receptacle and a 30 amp 120/240 volt receptacle. (I would have blown the 30 amp breaker on my shore connection running three A/C units.)

I was using the 30 amp 120 volt receptacle and was able to run all three rooftop A/C units plus the 1500 watt water heater from the 120 volt 30 amp outlet on the generator. I'm sure I was pulling over 40 amps so I only ran the water heater for a minute or two. (The 30 amp receptacle on the generator has no breaker.)

You answered your own original question by plugging into the 30A connection on the gen.

The answer is, you WILL have to use the 30A 120V outlet and using the 120V only mode which parallels the two inverters.

You CANNOT use 240V mode due to the inverters not having enough surge capacity.

If it was me, I would pack up that gen and send it back for a full refund and buy a smaller, lighter, cheaper 3KW inverter gen....
wa8yxm
Explorer III
Aug 05, 2013
Is there a 120/240 volt switch on the generator? IF so then here is the problem.

You have two inverters in there, each is 1/2 the 6300 watt rating of the genny, When in 120 volt they are parallel and synced so they provide 6300 watt at 120 volt However in the 240 volt they provide 1/2 of that to each leg or a total of 6300 watt at 240 volt.

The result is..... You overload at 50 percent (just one leg is overloaded).
belfert
Explorer
Aug 05, 2013
Gdetrailer wrote:
belfert wrote:
dougrainer wrote:
Do you have 120 volts ANYWHERE in the RV when connected to that 50 amps? The AC units(compressor) has NO WAY to know what the supply is. Do the AC fans run? Do the compressors try to start? Doug

Yes, I have 120 volts to everything in the RV when plugged into the L14-30 outlet on the generator. The fans on the A/C units will run. The compressors just won't start on any of the A/C units.

I understand the 26 amps is surge only, but the compressor start-up is just a short term surge and after start-up it should only draw 12 to 13 amps.

I managed to run all three of my A/Cs and the 1500 watt water heater at the same time through the 120 volt 30 amp connection. I had to be pulling over 40 amps, but I didn't get out my clamp-on amp meter to check. I only ran the water heater for a minute or two.

Running high surge equipment on 30A shore power means nothing... Basically shore power is "unlimited" when it comes to surge currents, generators not so much.

I wasn't running on shore power when I was using 120 volt 30 amp connection. This generator has both a 30 amp 120 volt receptacle and a 30 amp 120/240 volt receptacle. (I would have blown the 30 amp breaker on my shore connection running three A/C units.)

I was using the 30 amp 120 volt receptacle and was able to run all three rooftop A/C units plus the 1500 watt water heater from the 120 volt 30 amp outlet on the generator. I'm sure I was pulling over 40 amps so I only ran the water heater for a minute or two. (The 30 amp receptacle on the generator has no breaker.)
Gdetrailer
Explorer III
Aug 04, 2013
belfert wrote:
dougrainer wrote:
Do you have 120 volts ANYWHERE in the RV when connected to that 50 amps? The AC units(compressor) has NO WAY to know what the supply is. Do the AC fans run? Do the compressors try to start? Doug

Yes, I have 120 volts to everything in the RV when plugged into the L14-30 outlet on the generator. The fans on the A/C units will run. The compressors just won't start on any of the A/C units.

I understand the 26 amps is surge only, but the compressor start-up is just a short term surge and after start-up it should only draw 12 to 13 amps.

I managed to run all three of my A/Cs and the 1500 watt water heater at the same time through the 120 volt 30 amp connection. I had to be pulling over 40 amps, but I didn't get out my clamp-on amp meter to check. I only ran the water heater for a minute or two.

Running high surge equipment on 30A shore power means nothing... Basically shore power is "unlimited" when it comes to surge currents, generators not so much.

Generators have an extremely limited surge current that they can support, inverter styles even more limited.

If you had a built in gen which has 240V what they tend to do is have ONE 30A circuit and ONE 20A circuit.

In your case you have TWO 20A circuits no matter how you decide to cut it up.

Your gen DOES not have the surge capacity to get the job done, if it was a non inverter model you most likely would be able to get away with that wattage.

You may need to look at adding hard start kits to the A/C units to see if that helps.

Personally I would return or sell that gen and find one that isn't an inverter type for your setup at perhaps a bit higher wattage.
dougrainer
Nomad
Aug 04, 2013
Explain your Year/Brand/Model Motorhome/RV. What Brand Model AC units. Do you have an EMS system (Intellitec or PCS). Is this a standard RV(regular builder) or is it something you have had built? Doug
belfert
Explorer
Aug 04, 2013
dougrainer wrote:
Do you have 120 volts ANYWHERE in the RV when connected to that 50 amps? The AC units(compressor) has NO WAY to know what the supply is. Do the AC fans run? Do the compressors try to start? Doug

Yes, I have 120 volts to everything in the RV when plugged into the L14-30 outlet on the generator. The fans on the A/C units will run. The compressors just won't start on any of the A/C units.

I understand the 26 amps is surge only, but the compressor start-up is just a short term surge and after start-up it should only draw 12 to 13 amps.

I managed to run all three of my A/Cs and the 1500 watt water heater at the same time through the 120 volt 30 amp connection. I had to be pulling over 40 amps, but I didn't get out my clamp-on amp meter to check. I only ran the water heater for a minute or two.