Generac generator troubles..

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Johnrf76

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Aug 11, 2018
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We have a 1998 Damon Daybreak with a Generac q55g onboard generator.  I went out today & started the generator to warm up the oil so I could change it.  The generator started fine, but I noticed that none of the tv lights were on nor was the coffee maker or microwave.  I tested a couple outlets and none of them had any power.  When plugged up to shore power, which it normally is , things work fine.  I initially suspected the transfer switch but after pulling the plastic cover off of the generator, I noticed that the red light on the voltage regulator is not lit up.  It doesn't light up when starting the generator nor does it light up when the generator is running.  If the voltage regulator is indeed bad, could that be keeping current from entering the RV?  I haven't found a real good spot to check the generator output with my multimeter.  I tried on the backside of the circuit breakers, but I never could get a reading of any kind. 
 
I would expect that if there is no voltage from the generator the engine will shut down almost immediately. This is a fail safe mechanism to prevent further damage, your unit should have it. The voltage regulator controls exciter voltage going to the rotor, if it fails the generator won't produce. Can you easily access the brushes? If so check for voltage there to see if the exciter circuit is working. The brush closest to the end bell should be positive.
 
The generator stays running, even if I throw both circuit breakers on the generator.  I'm not sure about accessing the brushes, I haven't gotten that far into things yet.  It seems quite possible that the voltage regulator could be bad.  It might be worth getting one to try..
 
You can use a Non-Contact Voltage Tester and follow the electric wires see where the electric current stops.  https://www.amazon.com/gp/product/B000NBA8F8/ref=ppx_yo_dt_b_asin_title_o03__o00_s01?ie=UTF8&psc=1
 
So my new voltage regulator came in today.  I installed it, cranked the generator up and same situation.  No red light on the voltage regulator and no power to the coach.  I took the cover off the junction box in the roof of the generator compartment and using my multimeter was only able to get 2.7 volts on the hot coming from the generator.  I'm afraid a trip to a service center may be in order...
 
I'm not sure about yours, but some generators need to be flashed. If yours is one of them, the procedure will be in the service manual.
 
Thanks for the tip.  I checked the manual, and it stays the the field is excited, or flashed, each time the engine is cranked.  That is.....assuming it is working.
 
Johnrf76 said:
The generator stays running, even if I throw both circuit breakers on the generator.  I'm not sure about accessing the brushes, I haven't gotten that far into things yet.  It seems quite possible that the voltage regulator could be bad.  It might be worth getting one to try..
Click to expand...

NOT so on a generac. That's only on SOME onans, some onans will run too.
 
Johnrf76 said:
Thanks for the tip.  I checked the manual, and it stays the the field is excited, or flashed, each time the engine is cranked.  That is.....assuming it is working.
Click to expand...

There are several trouble shooting guides on the net for your generator. You have to go thru step by step to find out where the problem lies. If it stopped working after a long storage, it could need the slip rings cleaned, the procedure is in the trouble shooting guide. The exciting voltage is supplied by the start switch to the slip rings. if the slip rings are not making good contact or the brushes aren't making good contact there will be NO voltage. Tip, very hard to trouble shoot one while it is still installed.
 
Shame on me for not responding earlier as I hate un-resolved posts...I ended up taking the generator to a Generac technician, who was able to repair it.  One issue was some wires shorted out in the junction box of the generator bay which also affected part of the control board.  $300 later, works great.
 
My Generac 65 G quit making AC power while I was driving down the highway.  :-\
No AC power coming out of genset.  Genset engine starts and runs fine.
I have done a lot of tests.
Obviously, I'm pretty familiar with the unit because last year I replaced the magneto in the engine.  Not afraid to work on it.
I might have the same issue as Johnrf76 has spelled out in above posts...
I have spent many hours trying to find any service center in 500 mile radius that will work on a Generac RV genset.
Hopefully John will see this post and post contact info for a Generac repair site.
 
You probably can find a local Dealer / repair on their website
http://www.generac.com/dealer-locator.aspx?category=1
 
I tried the Generac Dealer Locator.
In a 500 mile radius of home (Havana FL) I called dozens of the listed... Most said they don't touch RVs just home gensets.
I found a great one in Augusta Georgia, they could look at it in a month.  :(
Many told me, "Just put an Onan in it."
Some said "If you pull it out and bring it to me, I'll look at it."

But, the RV community is great.  I received a pdf of the original Generac troubleshooting manual.
And. I've read of similar problems on the forums and their resulting "cures". 

Instead of pulling the trigger on a $7,000 retrofit, I'm gambling $250 and ordered a new voltage regulator.

Chances are the retro fit will now cost me $7,250.  LOL 

I'll keep you posted.
 
Yahoo !!!!
This forum is so great !!!
Another example...

Johnrf76 posted how he got his Generac successfully repaired. 
Another forum member wrote how a tech changed out the Voltage Regulator.
So I purchased a new regulator and installed.
And the Genset is operating wonderful again!

$250 vs.  ~$7,000 to change out to an Onan.

For those who later are searching for answers...

The Voltage Regulator with original number 74074  is now part number 0830480SRV.

It's hard info to find with this forum.

Thanks to all who post solutions out here!
 
Quietpac 75D......works fine one time producing 122 V.......Next time voltage may be only 97.....next time works fine and just shuts voltage to zero................next time ......122v to 0  to 122 to 0v.          Thinking Voltage Regulator???????????  What do you think?
 
Two options and that is one
The other is a screw loose (Well a connection) and yes. on the voltage regulator (or a bad solder joint)

Oh the joy  (not related to generator) Fridge works again. New amish built cooling unit. Professionally installed.

I know know exactly how to replace the cooling unit:
Step one: Call Rachel the RV-Girl (The professional installer).
 
ron56c said:
Quietpac 75D......works fine one time producing 122 V.......Next time voltage may be only 97.....next time works fine and just shuts voltage to zero................next time ......122v to 0  to 122 to 0v.          Thinking Voltage Regulator???????????  What do you think?
Click to expand...

First thing I'd check are the brushes and slip rings.  The voltage regulator board feeds the field coils on the armature through them and power is taken out of the stationary coils on the generator frame ... the opposite of normal motor operation.

If the brushes or slip rings are dirty or bad, the regulator board has to work harder to supply adequate field drive and may fail again, as well as giving intermittent voltage output if it can't push enough current to the field coils.
 
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