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Topic: Important to check generator brushes... & have a good Phoenix generator shop. (Read 736 times) previous topic - next topic

Important to check generator brushes... & have a good Phoenix generator shop.

About a month ago, after turning off our roof airs to let our generator cool down, our Progressive Industries EMS display notified us generator output was intermittingly slipping down to below 60 volts.  A call to Jeff Jones, Power Tech's Service Manager and helpful guru told us to check brushes.    (Power Technology Southeast 352 435 4416 )

Also Jeff insisted that with 4,000 hours on our generator, we change the end bearing, which has nothing to do with low voltage.  If our $10 bearing fails we will probably total our generator back end and have a multi-thousand dollar repair.

With these two looming generator issues, we searched for a Phoenix repair shop and found a gem we HIGHLY recommend, who is also authorized by Power Tech:

ISSCO Generator, owned by Robert Featherstone, who is a one-man show who does not have a physical shop and mainly operates mobile where the RV is parked.
Robert's contact info is 602-803-7974.  Issco Generator and RV Repair  residence 12675 N. 73rd Ave.  Peoria, AZ 85381  isscogenerator@hotmail.com
We found Robert very knowledgeable, helpful, competent and ethical.   

Turns out our low voltage was caused by worn brushes.  The inner brush was worn down a little.  The outer brush was not worn much, but instead the brush wore a bad groove in the one slip ring commutator, maybe caused by a stronger brush spring or a piece of dirt getting under the brush.  The groove is a problem as it could prevent new brushes from making a good contact.

Robert spent a lot of time with emery cloth between his fingers sanding the slip ring until it was smooth again.

We have now learned that generator back-ends are either brushless or brushed.  Most older are probably brushed and many newer are brushless, each with their advantage.  Our generator is brushed and has a metal plate that protects the end bearing and brushes.  To remove our brushes to check them, only required me to remove cover-plate's two small bolts, remove two small bolts holding the brush assembly in place and then lift out the brushes to examine them and slip ring for wear.  And replacing our brushes just required disconnecting the two wires attached to the brush assembly.

Well, over the 16 years of owning our Foretravel & 4,000 hours of generator use, I never thought about examining brushes for abnormal wear, so even though they were easily available to look at and probably being able to catch the one badly wearing brush & slip ring, it took very low voltage to get our attention.  If the slip ring was damaged beyond field repair, the $300 fix could have cost us $3,000.  And now that it has been sanded down, it probably can't be sanded again.

So I think, if others have a brushed generator that can be easily examined, it would be a good idea. 

The longer the generator is not used, the more chance the end bearing sealed grease could migrate, increasing the chance for bearing wear and possible failure.  We periodically run the generator under load, and between runs, have just cranked the generator for a moment to rotate the bearing.

Our repair cost:
$73.50 - brush assembly (PowerTech parts cost)
$200.00 Robert labor
$50 service call
$9.90 - bearing purchased locally at Bearing-Belt & Chain, 729 E Buckeye, Phoenix 602-252-6541, (our bearing part# KOY 6304 ZZ C3).

To insure the best outcome, we also decided to replace the two 35-amp breakers $86, and voltage regulator $237.

Some photos attached