Generator Failure

Topic: Generator Failure (Read 2045 times) previous topic - next topic

Generator Failure

February 07, 2012, 11:08:53 pm

Today i received some really bad news. I've been battling erratic generator performance since December; the Isuzu would run fine, but the 12 kw generator wouldn't reliably produce AC. After lots of investigating, I had narrowed the problem down to the AVC-Analog Voltage Control, i.e. voltage regulator. But I wasn't positive and I need to have the generator working at the end of next week when the Winter Range cowboy shooting international championship begins.

So I reluctantly scheduled an appointment with Divine Coach Care, the Power Tech dealer in Phoenix. Jon, the tech, quickly confirmed that my diagnosis was correct and replaced the AVC. While he got AC, the voltage was erratic, varying between 75 and 149 volts! After an extended discussion with Power Tech, they concluded that the front end had to be replaced. That's the whole electrical side of the generator, which has less than 1000 hours run time. The good news is that Power Tech has the replacement front end in stock, so it can ship tomorrow. The bad news is the cost: $2,700 for the part plus shipping, plus 6 hours labor to pull the generator, remove the failed front end, and install the new one. At least I'll have a working generator when the shooting starts!

Re: Generator Failure

Reply #1 – February 07, 2012, 11:22:39 pm

Been there, done that. Roughly 500 hours on our 10kw PowerTech (which is now a 12 kw PowerTech since they don't make the 10 KW end anymore).

www.foreforums.com/index.php?action=media;sa=album;in=234

I think I also posted a link to a YouTube video showing the loose rotor was well.

Yup - here's the post/thread Kubota electrical generation failure

Michelle

Re: Generator Failure

Reply #2 – February 07, 2012, 11:46:50 pm

600 watts of solar panels sounds better and better.

Craig

Re: Generator Failure

Reply #3 – February 08, 2012, 12:22:33 am

Speaking of Generators: I have the Onan 7.5KW DKD generator. It has 3 cylinders. I have read the owner's manual from cover-to-cover, but I can't determine the actual make of the diesel engine. Does anyone know if it's an Izuzu or a Kubota? Knock on wood, it is working very well, but I have always wondered what kind of engine it is. I'm thinking Kubota, but don't know for sure.

Don Hay

Re: Generator Failure

Reply #4 – February 08, 2012, 05:11:32 am

Don, The DKD uses the Kubota engine, that engine has never been a problem unless it had sat unused for 10 years, then the fuel system is fouled up. Also never an issue with the generator stator nor rotor, in fact the biggest issue we have seen with the DKD is the fan belt needs replaced about every 3K hours, A bookmobile gets a lot of hours run time.
Dave M

Re: Generator Failure

Reply #5 – February 08, 2012, 07:20:25 am

Ouch, but at least there was one in stock. I saw Steve and Michelle's parts at MOT when I was there. I am thankful I have not had that issue yet but I am sure it will happen to all of us as our coaches age.

Re: Generator Failure

Reply #6 – February 08, 2012, 08:44:43 am

I wonder what failed in the generator end? Windings? Bearings go out and let something rub? Heat from excess current cook insulation? It'd be nice to be able to do a bit of pre emptive maintenance. Amos, are you keeping the old part? Might be able to take it to a good motor shop and have a rebuild done.

Re: Generator Failure

Reply #7 – February 08, 2012, 12:11:40 pm

I'm not planning to keep the part. I'm assuming there is a healthy core charge. Is that right, Steve? I don't think I'm interested in spending the additional money to have the current one rebuilt on the off chance we might have another failure 13 years from now.

The only thing we might have done to provoke this failure might have been not replacing the insulation soon enough. I guess the black powder getting sucked in might have caused overheating. I don't know.

Re: Generator Failure

Reply #8 – February 08, 2012, 01:56:31 pm

Dave M.: Thanks for the info. I replaced the fan belt at 2200 hours; it looked like it had never been changed: chunks of rubber were missing, yet the cords were still intact. The belt is extremely difficult to reach as the generator doesn't slide out. At the time it was "only" 16 years old! The generator now has 2650 hours on it and still works well.

Re: Generator Failure

Reply #9 – February 08, 2012, 03:27:40 pm

Don, Don't laugh, but that DKD with normal maintenance, (Oil & Oil filter, Fuel filter & change coolant every five years), it will be running fine long after you really don't care, have seen one with nearly 12,000 hrs, still did the job just fine until they bought new bookmobile, the new Kohler generator in it had to be changed out to an Onan at 3,600 hrs, now they are happy again.
Yes for some reason the fan belt is the weak link on that model, The DKC is the 10 kw 4 cylinder version, in new bookmobile, it enjoys the same rep.
Cheers
Dave M.

Re: Generator Failure

Reply #10 – February 08, 2012, 03:38:14 pm

Last fall visiting Nac, Mike @ MOT, showed the generator end from Steve & Michelle's unit, the sad part, the exciter rotor came loose on the shaft, causing the failure, not a case of torque up again and on your way, too much damage overall, sad.
Like John said, sooner or later, we might need one too. In my case, my genset now has 1980 hours and about 3,000 hrs, I will take apart and replace the bearing at rotor end, of course will check very close to the exciter rotor plus all parts and connections, corrosion, floppy/loose wiring, insulation that might be rubbing & thin. Lots of goodies to snoop over, includeing rubber mounts. radiator hoses, exhaust for cracks & mounting.
I hope I can wear the generator out, proves I have had a great time with the coach. Besides am not trying to save it for the DW's next Buffalo.

Re: Generator Failure

Reply #11 – February 08, 2012, 04:09:30 pm

Quote from: amos.harrison – February 07, 2012, 11:08:53 pm

The good news is that Power Tech has the replacement front end in stock, so it can ship tomorrow. The bad news is the cost: $2,700 for the part plus shipping, plus 6 hours labor to pull the generator, remove the failed front end, and install the new one.

Brett,

Just FYI I pulled up parts cost on our repair. $21xx from PowerTech for the 12 kW generator end which jives with PowerTech's online retail pricing

Power Technology Southeast Inc - 12kw Exciter Generator End

Looking at our 10/2010 invoice from MOT, we were charged that, less 10% discount and that included any freight charge. A little over 10 hours total for diagnose and repair (our genset is in a quiet box, so that added a little to the labor). All new extended life red coolant, and a new voltage regulator. Plus shop supplies (towels, rags, bandaids, ibuprofen....)

I believe the damaged end was valued at somewhere between $50 and $75, all as scrap metal. We were offered the old parts, but let MOT keep them. It was worth it since that let Dave M. take a peek at the remnants a few weeks later.

I'm very curious what the failure mechanism is on yours. If you get the chance, post photos.

Michelle

Re: Generator Failure

Reply #12 – February 09, 2012, 12:02:12 pm

Steve,

That 12KW generator end doesn't look a thing like mine. Did your new one look the same as the old, or has there been a major design change?

Re: Generator Failure

Reply #13 – February 09, 2012, 01:57:18 pm

Quote from: amos.harrison – February 09, 2012, 12:02:12 pm

That 12KW generator end doesn't look a thing like mine. Did your new one look the same as the old, or has there been a major design change?

Brett, I don't know on either account. That's the only 12 kW end on PowerTech's site so I grabbed it for reference (but the price is similar to the list price ours was 16 months ago). I know the 10 kW end used in our generation is no longer available, only an 8 and a 12 kW.

It could be that the ends we have in our gensets are not shown on their parts page (I didn't cross-reference applications), but may be worth double-checking the price.

Michelle

Re: Generator Failure

Reply #14 – February 09, 2012, 04:46:18 pm

The generator end used by Power Tech are off shore built, price seems to be the qualifing requirement. Years ago the generator ends were mostly built by a company in Lancaster Pa, (Called Pancake model) It was sold to Marathon Generator, seems they no longer provide the unit at a reasonable price, but is a first class unit. So guess the old saying, "you get what you pay for" is still in effect. That is the unit I put over 6 K hours on in the MCI conversion, never any issues. New owner loves it too.
Cheap is not spelled the same as value or quality.
Sad fact
Dave M

Re: Generator Failure

Reply #15 – March 05, 2012, 07:03:41 pm

Bumping this to ask Brett if he would chime in as to what the failure mechanism was.

Michelle

Re: Generator Failure

Reply #16 – March 05, 2012, 08:17:35 pm

Is there a "Hit List" developed on this Forum of the Good, Bad, Ugly?
Searching is fine if necessary, but wonder if there is a place where we can see the equipment on these coaches that work or not and specifics on costs for repair or replacement or guidelines on steps?
I've noticed Aquahot systems being Top choice but also being repaired or replaced, but do not believe I have noticed cost issues on either. Time to fix/percentage of failures/ age/issue of concern/ etc.... or life of units as well?
Shocks? When? See Koni models explained, but costs/shock to buy or with an install and difficulty factor-to install ect. Comments?
Tires, Michelins suggested, but Hankoon's stronger sidewalls or just go to a higher grade of Michelins? Goodyears passe?
Age of tires; - that 6 years is -reasonable time to change out? I don't want to blow unnecessary $ if not needed nor I believe would anyone else reading this, but I would never accept the conscious failure of my decisions that could take out an innocent driver/passenger somewhere.
I will leave my questions short hopefully to find such a location and if not maybe find the information even if now not in one place.
On generator failure, over the years I have thrown them away rather than replace as to cost an also poor information that I had. How nice if I/we had tonnes of info.
Believe me, I truly believe this is the best of the best forums I have ever read and while I might be asking a question that does not want to be answered by some, it is one of interest to many.
thanks.
ron sheridan

Re: Generator Failure

Reply #17 – March 06, 2012, 07:47:40 am

Michelle,

I'm sorry I can't answer your question. Neither I nor the tech could find anything obvious wrong with the original generator. The bearings were fine, and there were no burn spots evident. PT required that the regulator be replaced to honor the warranty on the new generator end, yielding a total cost of $3,600 for parts and labor. My parts cost was much higher than yours because my unit is older.

Re: Generator Failure

Reply #18 – March 06, 2012, 10:31:48 pm

My power tech went out with only 75 hours on it... Power tech told me it was my reg and sold me a new one for around 300 bucks. installed it and still no power. Next step.. Power tech told me I had a dead head and I needed to buy a new gen end ($2,500) plus a 3RD reg ($300) Fixed it.
When it died I had it running for around one hour in 100+ deg Texas heat. I think the power tech unit is just low end junk but that's just me.. Hope you get it fixed because its fixing to get hot outside

Re: Generator Failure

Reply #19 – March 07, 2012, 10:37:46 am

How old is your generator that has only been run 75 hours?

Re: Generator Failure

Reply #20 – March 07, 2012, 06:44:01 pm

It's a 1996 u270,this happened in 2009 so it was 13 years old...I've got around 200 hours on it now

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