Do You Really Know Your Onan Generator?

[rowiebowie]

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Earlier I posted a request for technical help to fix my Onan Generator's low power output http://www.airforums.com/forums/f448...qg-186103.html. I made the successful adjustments yesterday, and my problem was solved. However, I feel the underlying problem warranted it's own thread.

My generator was running acceptably (or so I thought). It started my A/C without problem, ran smoothly no matter the load, and gave no indication it was putting out marginal or potentially damaging power. I only tested the generator's output as an after-thought when checking to make sure I was getting adequate current through my 20A household plug to run my new A/C.

Using my Progressive Industries EMS-PT30X plugged into the galley outlet through an adapter, I found the low generator output. I was getting 117 volts at rest, but only 57 Hz. Output dropped to 106 volts/ 53 Hz under a load of 12-13 amps.

I've never seen another post on generator output. Sure, there are many posts on running issues, inability to start A/C's, noisy operation, etc.

Is it possible my Onan problem is unique to me, or is it an overlooked potential problem for many others?

How many more generators out there get serviced and never adjusted to proper output levels? Probably more than we think and worth testing, in my opinion.


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[AtomicNo13]

I check mine before every use for frequency and voltage. Its simple, if I recall, 128 volts is a perfect 60 hz.

[rowiebowie]

Originally Posted by AtomicNo13

I check mine before every use for frequency and voltage. Its simple, if I recall, 128 volts is a perfect 60 hz.

If your readings are at rest, you should be good provided you don't drop much under load. If that is your reading under load, you're really doing good. Glad to hear you're checking it.

The Service Manual on my Onan gas 2800 KV says no load max is 130v/63Hz, while under load it should be 120v/59.5Hz minimum. I'm now getting the proper Hz under both conditions, but slightly less voltage (-3 to 4 volts) whether under load or at rest, but I should be good.
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[AtomicNo13]

I use a freestanding Emerald III, 6500.
My rpms never flinch more than 2 volts, even with 2x ac, fridge, converter, and other stuff running at once. This genset is a beast!

[rowiebowie]

Originally Posted by AtomicNo13

I use a freestanding Emerald III, 6500.
My rpms never flinch more than 2 volts, even with 2x ac, fridge, converter, and other stuff running at once. This genset is a beast!

Your gen certainly is!

The 2800 Onan is up to the task for my 30A rig, but it needs to be producing it's specified output. Unknown to me, mine was not. I'm glad I found out before I harmed my new A/C. Although I did run it for 45 mins. off generator when I installed it last month. At 53Hz and 106 volts, it wasn't good for it, I suspect.
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[BigTexRex]

Have you tried to adjust the volts and Hz output? They are both adjustable...I had to do mine. If the adjustment technique is not in your owners manual you'll be able to find it online.

[rowiebowie]

Originally Posted by BigTexRex

Have you tried to adjust the volts and Hz output? They are both adjustable...I had to do mine. If the adjustment technique is not in your owners manual you'll be able to find it online.

Maybe you missed it in my first post, but I did the adjustment per the Service Manual and fixed my problem. The reason for this Thread is to let others know my low output problem and to suggest they may want to test their generators.

[rmkrum]

Yup. And it’s also a darn fine idea to have reliable instruments in the rig to tell you voltage, current, and frequency of the power that generator is putting out...cuts down on the nasty surprises...