generator/electrical problem

[PSU_RVr]

Having an issue with what I assume is my generator. I can run the generator and normally don't have any issues. I can run electronics, the microwave works, etc.
However, when I try to run the AC, something resets. The AC will actually start running for a couple seconds and blow cold air. But then everything resets. Not really sure what is happening. What I see is the electrical display panel - that shows I'm connected to 50amp service - will turn off and back on like I just plugged in.
The generator never shuts down. I am only running 1 AC unit, and it doesn't matter which one I run.
There are no issues when I'm on shore power. I can run both AC units without issue.
I don't have a lot of expertise with generators. I know the oil level is good and the oil was recently changed.

[PSU_RVr]

Took the RV to a repair shop. They found a faulty ATS was tripping on the generator side. Replaced it and all's good now.
Thanks for all the suggestions.

[superk]

Oh wow, sorry I must have overlooked that.

I then retract previous statement. Running in tandem is not only not necessary, its a waste of fuel, and could actually be killing your EMS.

[dougrainer]

enblethen wrote:
Unless I am reading the OP's second post he is trying to run shore power and genset at the same time. He says running in "the genset and AC in tandem". Some Transfer switches don't like this!

He states that he is not running both, just that on shore power both AC's have no problem. Only when Genset is running. As to your statement that some Transfer switches don't like BOTH Shore and genset. NOT TRUE. On Genset, IT will be in Genset mode. I have NEVER seen a conflict on an ATS when both Gen and Shore are connected. IF you have such a problem, your ATS is defective or miswired. The purpose of the ATS is to be able to have BOTH sources available without a conflict or problem. Doug

[mtrumpet]

enblethen wrote:
Unless I am reading the OP's second post he is trying to run shore power and genset at the same time. He says running in "the genset and AC in tandem". Some Transfer switches don't like this!

X2.

I'm leaning toward some sort of transfer switch issue at this point in the discussion.

[enblethen]

Unless I am reading the OP's second post he is trying to run shore power and genset at the same time. He says running in "the genset and AC in tandem". Some Transfer switches don't like this!

[dougrainer]

WHICH EMS (energy management system) do you have? I guess an Intellitec, but confirm. You stated the AC runs for a "few" seconds, blows cold and then system resets. CANNOT HAPPEN. The AC will NOT run for a "few" seconds and also blow cold air. NEVER. MOST AC units have at least a 2.5 minute delay before the compressor starts. It may be as little as 10 seconds on some models, but it will still take a few minutes for the system to generate cold air. The EMS system (Intellitec) just senses amp draw and the system just reads the 12 volt signal from the Genset to let the EMS know if shore or Genset. You really need a 120 volt reading of the Genset. Does the Genset skip or lug down when this problem happens? For the display to go off and back on would indicate a 12 volt problem. The EMS systems use 12 volts to power them up. Doug

[superk]

I doubt that its the ATS because it IS effectively switching from generator power to shore power, and your equipment works fine on shore power. It COULD be the relay on the generator side of the ATS, but even then, thats doubtful.

It sounds more to me like an issue with the generator itself. Most likely dirty slip rings are causing the voltage regulator to work too hard, and its shutting down. I had the same issue happen to me 2 weeks ago. I know its not my voltage regulator as I just bought a brand new one from flight systems and installed it.

Went out with my 'Slip stick' also manufactured by flight systems, started the generator, cleaned the rings, restarted the generator to reset the voltage regulator, never had a problem since.

http://www.flightsystems.com/rv-generator-controls-repairs/slick-stick-slip-ring-cleaner.html

Thats where I bought it from. Reliable seller, well known.



My generator is a 5.5k onan marquis. as well. I have all too much experience with this unit.

This is the quickest and easiest thing to check, and it requires to disassembly of anything. Try it first!

[enblethen]

ATS= Automatic Transfer Switch. I believe it is fighting the two sources.

[PSU_RVr]

Sorry for posting an not getting back in timely manner. Too much going on all over the place.
The generator / AC tandem has worked in the past.
Not sure what you mean by the ATS or ATF ( I assume either someone had a typo or the same thing has more than one name)
As for "what do I mean everything resets", it's hard to say. Everything on the DC side seems fine at the time. The radio keeps playing. Lights stay on.
Everything on the AC side shuts off. And if I watch the control panel, it only briefly goes dark, then starts up like I first turn on the generator.

Sounds like my next step is to reproduce the problem and read the volts coming off the generator.
It's a 5.5kW Onan

[Ivylog]

What size generator? Sounds like your power management is seeing less than 109 volts which causes the system to shut down and then it resets. Need to know your voltages.

[rgatijnet1]

I could be that the AC starting capacitors are about to fail and are drawing too much current when trying to get the compressor going. This overloads the generator but it is not enough to trip a circuit breaker. If the voltage drops too low from the excess current draw, it can cause the energy management system to allow the transfer switch to reset.

[enblethen]

loose connection on genset feed or bad contacts in the ATS.

[mtrumpet]

What exactly do you mean by.."Everything resets"? Do you loose all power? Do you loose power just to the AC, but not everything else?..

[wallynm]

Could be bad breakers or ATF switch problem. Generator out put voltage could be a problem.