no input from Genset

[Keith Oliver]

I know nothing about electricity, so simple problems confuse me.  I have owned this coach for a year now.  The first trip (bringing it home) included some run time on the genset, but there were so many electrical gremlins that I don't know whether it worked properly then, or not.
I have not run it since.  Until tonight.  We are heading home after spending the winter south.  We have stopped for the night at a "Harvest Host" winery, so have no power, but our own.  So I turned on the Genset and got nothing in the coach.  Both breakers look OK.  The genset runs fine, but on the Heart Interface panel, clearly, no power is incoming.
Any idea what I should check first?  The Transfer switch bangs into action when I plug into shore power, so I think it works as it should.  
Once home, I will have time to tear into this, but I don't like the idea of wasting my efforts, if there are things I should avoid doing.

Thanks in advance.

[Phil N Barb Rodriguez]

I would try to turn the inverter breakers off then back on. This has happened to me a couple times on shore power and recycling the breakers seemed to fix the problem.

Won't hurt to try.....

Phil  

[LarryNCarolynShirk]

See if the circuit breaker on the genset has tripped.

Larry

[LEAH DRAPER]

I have had service people turn off the circuit breaker on the GenSet when being serviced and forget to turn it back on, so do check that.

[Bill Sprague]

The breaker on my genset will always trip at start up if the house batteries need charging and I run any other electrical appliance.   Apparently, the charger will draw 20 amps, or even a little more, in the start up cycle.  My Onan has a pair of 30 amp breakers.  That is significanly less than the pair of 50 amp breakers we get used to on the power pole.

If I try to run anything else, like the air conditioner,  heat pump or fridge it will exceed the capacity of the 30 amp leg 2 breaker on the genset.   If I wait a few minutes the charger calms down and I can run what I want.

[Edward Buker]

Kieth,

Sometimes the breakers will be "tripped"  and the lever can remain in what looks to be the normal position. Cycle on and off the breaker at the genset for sure and your main breaker at the panel and see if that fixes your problem. Beyond that measurements need to be taken at the transfer switch relays to know what is happening. If you are unsure of how to do that in a safe way, it would be best to find a friend or hire someone who has some knowledge of what comes next.

later Ed

[Richard And Babs Ames]

The Onan Generator works off an inverter. We had to replace ours for about a $1000 a few yeas ago.

Start at the gen set to see if it is putting out power then the Tara,NFC switch .

[Keith Oliver]

Ed: By "look ok" I mean I cycled both breakers full off and back on again, to no effect.  Is there another breaker somewhere?  Not in the main AC Panel above the bed. Is there another?

I now recall the sales guy running the AC while we were driving, off the Genset, so I know it worked properly last year.  
Nobody has serviced it since then (other than I replaced the dirty air filter).  It has obviously new, clean oil, so didn't need anything else, and hasn't been run.

Richard: When you say "runs off an inverter" do you mean the genset is wired first to the inverter, then the transfer switch?  I don't think that is how mine is wired, as there is an obvious big wire from the transfer switch to the genset.

Plugged in again tonight, in a very quiet park, so I can't mess with it again till I get home, but thanks for the suggestions.  I'll let you know how I make out.

[Bill Sprague]

Ed: By "look ok" I mean I cycled both breakers full off and back on again, to no effect.  Is there another breaker somewhere?  Not in the main AC Panel above the bed. Is there another?

The suggestions here are about cycling the breakers on the Generator itself.  Not sure about yours, but mine is in the front and I have to push a button for the entire generator to slide out.  Then I have access to an hour meter, oil fill and coolant fill.  The connected pair of circuit 30 amp breakers breakers is there.  

[Edward Buker]

Kieth,

What Bill is refering to is the most likely candidate of being a simple fix. On the Genset, usually on the top near the hourmeter area, there is a double pole breaker. Cycle that breaker off and back on again, with the genset off, if you have not done that already. After you start the genset you can listen in the storage bay near the inverter for the transfer switch relays to click on after about 1 minute of operation. If you do not hear that it is another confirmation that no AC is being produced or the transfer switch circuitry is defective.

You need to run the genset 1hr a month under load to keep the brushes and commutator contact points burnished. It is also good for the engine mechanicals, seals, and injection system. Once you find out what has caused this problem and correct it, you will have fewer problems with exercising the genset than if it sits without use for extended periods of time. One last thing, be sure that the load is not severe when the transfer switch is kicking over. I would have the air units off and maybe the electrical element in the water heater if you have one. Once contacts are made and the genset is online you can add the heavy loads. This is to assure that all the starting current of the air units is not coming at once possibly kicking the genset breaker and it is easier on the transfer switch contacts. Hope this helps.

Later Ed

[Gerald Farris]

Keith,
The Onan 7.5 KW generator is a variable speed generator. Therefore since a generator can not produce a 60 cycle AC current unless it runs at a constant speed, the 7.5 unit produces DC current and changes that to 120V 60 cycle AC current with an inverter that is incorporated into the generator.

Gerald

[Richard And Babs Ames]

Thanks Gerald, the engine speed can vary with the load as the inverter is part of the genset.

[Keith Oliver]

Wow, what a lot of information!  You guys are great.
Now, here is what I have learned:  Don't start the genset while the inverter is under a big load.  When I started it, to take the load off of the batteries, the load was from the convection oven.  and that load apparently prevented the genset from taking over.  When I started it with no load whatsoever, after about a minute (maybe less) the output from the genset showed up on the panel, all working properly.  Now I don't know how much, if any, load the genset can handle on startup, but if it fails again, that will be my first attempt at diagnosis of the problem.
Gerald:  Mine is the 6.5.  Is it the same?

[Gerald Farris]

Keith,
The 6.5 KW LP (propane) Onan is a constant speed generator just like the Onan 10 KW and 12.5 KW diesel generators. Constant speed generators can produce 60 cycle AC current without an inverter, so no inverter is built into these generators.

Gerald