gmc generator has died

Submitted: Tuesday, Mar 18, 2008 at 10:50
ThreadID: 55662 Views:4626 Replies:7 FollowUps:6
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Two years ago I posted a review of my GMC 860w generator. It's had very little use since, and now, at 4 years of age, it has finally died...

The engine still runs well, but it's producing about 10VAC instead of 240, and 0.5 VDC.

GMC technical help were not very helpful, advising it is not financially worth repairing. They said the brushes, or voltage regulator could be faulty.

The "voltage regulator" is in fact a 12 microfarad capacitor, a CBB61, and tests OK for resistance and capacitance on my digital multimeter. I know that the test is not under load.

Brushes? Took the bearing end of the generator off and could see no obvious brushes. In any case, the armature end is hard to get to as a fan in in the way.

Both DC and AC circuit breakers are OK.

Anybody have any ideas? I am loathe to throw it out.

Incidently, I removed the muffler and emptied out about 200 ml of sludgy oil from it, and repositioned the exhaust pipe so it makes a better seal with the engine.
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Reply By: Member - Kiwi Kia - Tuesday, Mar 18, 2008 at 11:26

Tuesday, Mar 18, 2008 at 11:26
Hi Inspired, If it is an AC alternator then it sounds like you may have 'lost' some of the required residual magnetism. Any 'old time' electrician or auto electrician should know how to 'flash' the stator windings to get you going again. You may need to do it several times and have a reasonable current source. Last one I did was a real big sucker just before the Y2K bug was going to kill everything :-)) Company dragged out a huge standby machine that had not been used for years, fired it up and only got about 20 volts. I got the battery powered factory forklift, parked it alongside of the gennie and used jumper leads to flash the windings. First time voltage went up to about 50 volts. Second time about 120 then everything came right on third attempt.
AnswerID: 293313

Follow Up By: inspired - Tuesday, Mar 18, 2008 at 13:24

Tuesday, Mar 18, 2008 at 13:24
Thanks, Kiwi, I've read about that.... connecting a 9vdc or similar battery to the generator output and exciting the fields. Or, plugging in an electric drill to same, and manually spinning the chuck to generate power through the drill and into the windings....

Will study it a little more.
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FollowupID: 558971

Follow Up By: Member - Kiwi Kia - Tuesday, Mar 18, 2008 at 14:54

Tuesday, Mar 18, 2008 at 14:54
A 12 volt car battery would probably do but I would have no faith in an electric drill or a 9v battery. It's current not voltage that does the job.
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FollowupID: 558986

Reply By: Zapper - Tuesday, Mar 18, 2008 at 11:45

Tuesday, Mar 18, 2008 at 11:45
mine did the same but it was the capacitor. Mine was only putting out about 20v i pulled the one of my dads (same gennie) plugged it in and away it went, why don't you try a new one they don't cost a lot
AnswerID: 293315

Follow Up By: inspired - Tuesday, Mar 18, 2008 at 13:16

Tuesday, Mar 18, 2008 at 13:16
Got told by Bunnings' special orders department today --GMC told me to go through them -- that GMC do not stock spares for their generators.

Now there's great after-sales service, both by Bunnings, which has NEVER stocked spares for anything they sell....

....And by GMC which is prepared to give you a brand new machine within 2 years rather than stock a $2 plastic replacement part.

There are lots of internet references to the CBB61 capacitor--- almost all from China, none in Australia. But I will visit some exotic electronics shops to see if I can get one.
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FollowupID: 558969

Follow Up By: Truckster (Vic) - Tuesday, Mar 18, 2008 at 15:57

Tuesday, Mar 18, 2008 at 15:57
also nice to see bunnings wont swap dead electric tools (GMC drills etc) anymore..

You have to "SEND IT BACK AND WAIT".. in which case, you may as well just buy a good quality one and keep it for years.
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FollowupID: 558996

Reply By: Wizard1 - Tuesday, Mar 18, 2008 at 12:03

Tuesday, Mar 18, 2008 at 12:03
For another $98 you ca get another one.

They are designed as a disposible unit, hence why they are so cheap and GMC offer 100% money back or a one for one replacement.

Let it go and get a Honda
AnswerID: 293323

Follow Up By: inspired - Tuesday, Mar 18, 2008 at 13:20

Tuesday, Mar 18, 2008 at 13:20
Thanks, but for the little use it would get, a $1000 or $2000 Honda is not viable.
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FollowupID: 558970

Follow Up By: Shaker - Tuesday, Mar 18, 2008 at 14:27

Tuesday, Mar 18, 2008 at 14:27
You couldn't hire one for $25 a year.
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FollowupID: 558981

Reply By: Member -Signman - Tuesday, Mar 18, 2008 at 14:06

Tuesday, Mar 18, 2008 at 14:06
'planned obsolescence '!!!!!!!!!

If it's still a current model- wipe it over with a rag & take it back for exchange...Bought it 6 months ago & lost the docket !!!!


AnswerID: 293335

Reply By: inspired - Tuesday, Mar 18, 2008 at 15:57

Tuesday, Mar 18, 2008 at 15:57
Perseverance has paid off --I've fixed the generator.

Here's how...
I plugged my electric drill into the 240V outlet of the generator. I connected the drill's chuck to my cordless drill's chuck with a small bit of metal (a headless nail or drill bit will do).

The idea is to make the cordless drill spin the electric drill motor in reverse.
This generated electricity back through the windings, and within seconds, the generator was up and running again.

I'd first tried arcing the capacitor leads with a 9v battery...But this failed despite several attempts and reversing the polarity.

Wish I'd done it BEFORE I spent two days sweltering in the shed dismantling and assembling the thing so many times in the stifling heat.

Oh yes, open all the doors, and vent the exhaust to the outside via a long PVC pipe.

AnswerID: 293360

Reply By: Rut Tearer - Tuesday, Mar 18, 2008 at 16:02

Tuesday, Mar 18, 2008 at 16:02
Oh well 4 years is not the end of the world, sell it on Ebay as a spares machine for anyone that needs one. Engine would be good and other bits etc etc.
AnswerID: 293362

Reply By: Member - Doug T (FNQ) - Tuesday, Mar 18, 2008 at 20:47

Tuesday, Mar 18, 2008 at 20:47
CHINESE CRAP

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AnswerID: 293443

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