Quote:
Originally Posted by Jeff Niceswanger
Hi Rich,
A little info would be appreciated. We are just about to take our unit to the dealer but if there is something we could easily look at before we throw in the towel it would help. We have a 4000 Onan micro in a 2004 31 foot Four Winds( Serial #H020405714 Model 4KYFA26100K Spec K with 1500 Hrs.) and @ Columbus points race the starter drive busted in half. We dropped the unit out of motor home,ran to the Columbus Cummins dealer picked one up and changed it .Many busted pieces were throughout the shroud,so we took it all apart ,cleaned it all out, and re-installed everything. It took right off, and ran that whole day,but 24 hours later(next morning) it fails to start and sets a code 14(Over Frequency). It will run as long as you hold in the Start Button,and will run when its stone cold for about 30 seconds before it powers down. During this 30 second time-frame it has no measurable AC Output. I checked pins 1 and 10 and had 24 ohms so I thought the brushes were OK. Thinking it was a controller, we bought one ( #327-1413) and it does the same thing.I don't have a frequency meter, and I don't really want a problem in the future burning up appliances or such.I have recently been noticing my output meter on my 16 volt battery charger " wagging"). I never noticed that before and actually bought a new charger as I thought this one was getting ready to crap out.The new charger doesn't wag, so I just thought it was indeed the charger.Maybe its just more forgiving...BUT, I'm wondering if its related. Ideas?
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Jeff you did a good job describing your problems and what you did to try and diagnose it was spot on. If you have a good Ohm reading across those 2 pins that is very important info. It confirms the brushes and the rotor are good. You tried a Controller and had no luck. When the starter drive broke.....not uncommon... a piece may have somehow gotten inside the rotor/stator area. If the stator was damaged......well that would explain why you have no AC output and a shutdown. First thing is to do as was suggested and try to read the HZ or frequency when it starts and you can hold the button down to try and help you get this reading. Unfortunately if it has NO AC outout you may or may not see a frequency that makes sense....They will shut down if they overspeed and the controller looks at the frequency since it is directly coupled to the engine. 3600 rpm = 60 HZ...62-62.5 is what it should be with no load applied....
I would be OHM testing the stator. Since you knew what the rotor Ohm readings should be.....you must have a Service Manual......If you do read how to test the stator windings.....You can do this right thru the plug in connector. May show you a problem.....May not....
The stator has the coils or windings that are wound inside the outer housing of the generator....Stator as in stationary.....Rotor as in rotating....
If the stator has an open or shorted coil....well that is your problem.
I have done just about everything you can think of on a 4KY...and changing a stator is not that unusual....
They can be very tough to diagnose.....and often are.....