Motorhome Generator

[Kota]

Here's some info from googling kohler generator brushes that you might find useful.

http://blog.rv.net/2008/05/cleaning-...ushes-part-19/

[gunner]

Originally Posted by Kota

Here's some info from googling kohler generator brushes that you might find useful.

Cleaning Generator Slip Rings and Brushes – Part 19

That will have to be my next step, but it will have to wait, right now it is about 20 degrees outside and it is time to wait for warmer weather where I can slide the Generator out away from the motorhome to get better access. Is there a way to check the voltage regulator?
Here are my results from slowing down the speed:
No load 106.1 volt 61 hz
1338 watt load 101.1 volt 60.1 hz
With this low voltage I will be burning out my air conditioner compressors.

[Kota]

Put a big load on on it and run it hard for an hour. Heat lamps...

Might clean the slip rings like the article says.

The power conditioners/surge suppressers specify the low and high voltage limits. Check them out to get an idea of what is acceptable. I'm probably going to install a hard wired unit this spring. I'd hate to loose my compressors due to low shore power voltage. I've seen some pretty hoaky run down power distribution at campgrounds.

[gunner]

Originally Posted by Kota

Put a big load on on it and run it hard for an hour. Heat lamps...

Might clean the slip rings like the article says.

The power conditioners/surge suppressers specify the low and high voltage limits. Check them out to get an idea of what is acceptable. I'm probably going to install a hard wired unit this spring. I'd hate to loose my compressors due to low shore power voltage. I've seen some pretty hoaky run down power distribution at campgrounds.

I have 2000 watts on it right now has been running an hour voltage is 93.

[gunner]

I have added another 300 watts or so, voltage now is 91. If this works what should I be seeing a gradual voltage increase? It has now been running 1.5 hours, I was planning to run it another 2.5.

[mehes]

If you don't see any increase soon you might want to take a look at the regulator. Attached is what I believe to be the correct service manual for your generator if you don't already have it. Check out the section beginning on page 6-6 concerning the regulator.

kohler-7cm21-rv-service-manual.pdf

Hope this helps,

[garry]

Sounds like a really ugly 120VAC sign wave with spikes all over it.

The meter reading may be off due to the ratty sign wave, your meter reads effective voltage and you may clipping the sign wave or low peak to peak voltage. As others have said rusty, dirty slip ring or bad brushes would be my guess.

Be careful on what is plugged in when running the generator sensitive electronics do not like voltage spikes or bad frequency.

Only an o'scope will really tell you what the sine wave looks like.

[gunner]

Thanks for the service manual. Since I will have to do this outside and with Ice forecasted for tonight, rain then snow for next week with low in the teens taking the generator apart is going to have to wait. What I want to do is clean the slip ring and see what it will do. Everyone on the Kohler forum advised that should be my next step prior to doing anything else. Now that I have the engine speed set correctly for 60 hz under load I am finally seeing some progress.

[Kota]

Even with the generator running at full load the current to excite the armature isn't really huge. I would expect limited success on cleaning the brushes and commutator that way but It sure is worth the try. I was looking for the picture but couldn't find it. I was able to stick my iPhone in a tight spot and get some good pictures of the brushes and bad commutator of a heater motor on my Explorer. Used the same technique to find a good one at the junk yard.

I also have an inspection camera from Harbor Freight. That has been very handy for situations like this. Also works well for inspecting the dogs ears. Forget the DIY colonoscopy! 😳

[rmkrum]

Basically with any generator RPM controls frequency and current from the regulator controls voltage. Slip rings and brushes are the first place to look, then the wiring to them from the regulator, then the regulator assembly itself.

You are going in the right direction 😗


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[gunner]

Thanks for all the positive reinforcement. Based on the winter weather in Ohio it may be spring before I pull the Generator to access the slip ring assembly. I believe pulling the Generator is the only recourse since it is too confining to be able to work on it without pulling it.

[Vycan]

Here's a thought... Lectra Motive Cleaner. Can also be found at auto parts stores, Walmart, and on occasion RV parts stores.

The following is a long story to tell you this can of cleaner may get you going if it's only in need of cleaning, and you can get access with a spray straw to have a solution before it warms up.

Sometimes when getting access to the electrical parts due to confined spaces, you can get away with spraying it down with the above from the few access points.

Good example of use, the old I4 in GM vehicles in the 80's nicknamed the iron duke had a habit of developing an oil leak at the valve cover (among many other places) just above the starter and gumming it up. It was a weak point in the gasket and an easy inexpensive fix. Plenty of people would replace a starter every three months before figuring out the oil leak was causing premature failure. (why some mechanics were happy to do it without addressing the oil leak cause is another matter) I had a friend in college who's parents came to visit in an Olds 88 with this exact issue, they were having starter issues, and could not get the car started to get home. He called me for assistance, and after seeing it, determined it was from the oil leak, and they would be happy to pay me to replace the starter. Imagine their surprise when a (then) $5 can of electric parts cleaner fixed the issue enough for them to get home. My buddy and his dad then spent the next vacation at home replacing the valve cover gasket for a quality bonding moment. I even had the opportunity to participate via speaker phone.

Hope it helps.