Generator help

[ReevesRoadSchoo]

I have a champion 4000/3500 W old style generator. Everything I have read on here says it should start my AC. I have turned everything off except AC at the breaker box etc. It will run the fan but not start the AC. Do I need a hard start capacitor? Or is is something with the generator? The gen. will run a reciprocal saw that I used to test it. Thanks 🙂

[MrWizard]

the RV outlet has full power
the divided power is on the duplex outlets

[j-d]

HF manual for 8750 is Here. No Output Voltage Select Switch. Mentions dividing 120V load between the two 120V outlets.

[ReevesRoadSchoo]

Thanks for all the info.. The Champion is RV ready as in it has a 30amp plug but it is not invertor style. I am using cord that comes straight from camper and the AC works great on shore power. I will check spark plug etc. next I guess. 🙂

[TomG2]

Typical 4000/3500 watt Champion generators, like the three that I have owned, all were outfitted with 30 amp RV receptacles and would power anything the typical 30 amp park service provides. Good suggestion to load it up with hair driers etc. to see what it will handle.

[MrWizard]

i belive that generator is 120 'OR' 230v
meaning there is a switch to choose voltage
and in the 120v setting full power is availble on the large outlet
the earliest models had a 25 amp twist lock
and the later models a 30v TT/RV plug

saying you can only get 13amps is jumping to the wrong conclusion

besides the running power of the avg RV a/c is 12-13amps
only needs full power to start the compressor

he has an a/c problem not a generator problem

[j-d]

Downloaded the manual for HF's Predator 8750. It's got a 120V 30A three prong twistlock receptacle that could power an RV using an adapter to get from Twist to RV. I suspect, though, that the receptacle is rated to deliver half the 7000 running watts, or 3500, and half the 8750 starting watts. Might, just might, power all your RV stuff, but half of 7000 is still less than ONAN's 4000

[time2roll]

ReevesRoadSchool wrote:
I have a champion 4000/3500 W old style generator. Everything I have read on here says it should start my AC. I have turned everything off except AC at the breaker box etc. It will run the fan but not start the AC. Do I need a hard start capacitor? Or is is something with the generator? The gen. will run a reciprocal saw that I used to test it. Thanks 🙂

I would load it up with two hair driers on max for a generator test.

Then check the start cap in the A/C. You may not even have one depending on age.

I assume the A/C runs fine on 30 amp utility power.

[DrewE]

maillemaker wrote:
I never really understood this split you guys are talking about, so I'm glad I got in on this thread!

I've actually been considering pulling the Onan out of my RV and putting one of those Harbor Freight 8750 generators in its place. I figured a 23 Amp 120 V circuit would be enough. Sounds like not.

Steve

It is enough if you don't need more power than that. I think that generator should be able to start an air conditioner on either leg if there isn't much else being powered at the same time, not really much different from a 4 kVA 120V generator.

[2oldman]

maillemaker wrote:
I never really understood this split you guys are talking about, so I'm glad I got in on this thread!

Inverters (not inverter generators) can pull this trick too...if you're ever in the market.

[maillemaker]

I never really understood this split you guys are talking about, so I'm glad I got in on this thread!

I've actually been considering pulling the Onan out of my RV and putting one of those Harbor Freight 8750 generators in its place. I figured a 23 Amp 120 V circuit would be enough. Sounds like not.

Steve

[j-d]

Ever since I heard and understood how "jobsite gennys" can only deliver half their rating, on each of two 120 outlets, I've tried to explain that at every opportunity.
Unless the generator is "RV" like an ONAN etc. Or Inverter (like Honda and suitors) it's usually 240V made up of two 120V legs.
I think some of the Champions can deliver full output at 120V. I recall Harbor Fright having some that could do that as well, but discontinued.

[DrewE]

Artum Snowbird wrote:
You could also try running the A/C from shore power for a few minutes to get things lubricated, then disconnect and try restarting from the generator.

Restarting an air conditioner that was just running is much harder than starting one that has been sitting for awhile because you're trying to start the compressor against a full pressure head. That's the reason many thermostats have a two so minute delay before restarting the air conditioner.

If the generator is wired to be a 120V generator (i.e. it has a 120V, ca. 30A output), it should start the air conditioner with no trouble and if it is having trouble I would investigate such things as cleaning and adjusting the carburetor, replacing the spark plug, etc. If it's a 120/240V split phase generator, as many are, then it may well just not be powerful enough on one leg to start the air conditioner reliably. One way around that would be to get a 240V to 120V step-down transformer--probably an autotransformer internally--of sufficient power rating and connect it to the 240V output of the generator; that would give about twice the power for the air conditioner. Such transformers are not exactly small nor lightweight, though, and some that are available seem to be pretty optimistically rated.

In some cases it may also be possible to rewire the generator fairly easily to supply full power at a single 120V output. That is not always an option.

[2oldman]

sparkydave wrote:
The two 13 amp breakers on each 120 VAC outlet are the dead giveaway that the 4000 watt rating has a couple of caveats to it.

Yep. Caveat emptor. No wonder it won't run the air. 13 amps is probably an overstatement too.

[sparkydave]

2oldman wrote:

maillemaker wrote:
We tried to use a Harbor Freight 4000W generator to run our AC. It would do so, but only for a few minutes.

That sounds like a highly exaggerated wattage rating.

The 4000 watts is a peak load, it's only 3200 watts continuous. To further compound the issue, it's 3200 for both legs of a 240 VAC output, or only 1600 watts from one 120 VAC leg. The two 13 amp breakers on each 120 VAC outlet are the dead giveaway that the 4000 watt rating has a couple of caveats to it.