Evening guys and gals,

Been on the road quite a bit recently, matter of fact, still am but I just got word today from the RV shop near home that my 7.8KW Power Tech Generator (Kubota diesel) has a bad rotor and stator and needs a new head unit. I'm enough of a DIYer that I'd rather rebuild a part than replace it but generator heads are one area that I have very little experience with. Can someone tell me, are rotors and stators something that can be rebuilt or am I going to have to bite the bullet and buy a whole new head? If they are rebuildable, what's the best way of locating a reputable repair shop? The places that I've talked to up to this point have been parts changers.

Thanks in advance,

 

Ya might try a starter repair shop. They might be able to provide you with or rebuild your stator and rotor.

 

Yes, they can be rebuilt. Just like a motor, except it has funky excitation windings. It all boils down to how much $$$ to do it in the amount of time you have.
Get an upward price of a new generator end and then work down from there with a rewind.

A coworker of mine had one output leg of his 6Kva Generac RV genset output winding short to ground and a mom-&-pop shop down here rewound it for abt 1/2 the price of a new stator from Generac.
Ask around RV service shops about any industrial motor rewind shops that will rewind small gensets. That's what he did after he got the price from Generac. The big motor shop didn't want to mess with it but they were kind enough to refer him to the little shop.
This little outfit doesn't need to advertise as they have all the word-of-mouth work they can handle. They work on all sizes of generator ends. Small ones like yours and big ones too.

Maybe you can find someone up there that will tackle it like that.

 

Appreciate the info. They were quoting me over $2200 for a new generator head. I'll check into some motor rewinding shops and the like.

Thanks

 

Talked to Chris, my co-worker today. He gave me the names and #'s of the two shops that he dealt with.
Turns out, the bigger generator shop that was super helpful and (very busy) diagnosed the problem for him for free was: GEN-TECH here in Corpus. (361)813-2662
That fellow tested & verified the problem and then directed him to a smaller motor shop (Garza Electric, (361)884-3602)that actually rewound the stator for him for ~$220.00.

Maybe you could contact Gen-Tech and ask him if he knows of a good shop up around your neck of the woods that he could recommend?

This guy at GenTech told Chris that he was proud to see someone attempting to repair stuff themselves rather than just be parts changers.
He gave him some other tips on what else to replace while it was apart (bearings & shockmounts) and where to get the generic equivalents for them ( Grainger & local bearing house).

I haven't had to get anyone else to repair either of my gensets, but you can bet I'm keeping these two #'s written above my workbench.

 

Thanks for those numbers Rattler. I'll give them a call this week.

I got the gen set back in my possession today so now the disassemble and diagnosis can start. I already talked to several generator shops and motor rewinding shops in the area and am not real encouraged by the feedback. Either the price was too high or they were not very positive on the end results so I'm also exploring other options.

Does anyone know anything about ST generators? I know I'd have to fab up a mount but for 1/4 to 1/3 of what I was quoted for a new generator head, those look interesting. What's the catch? Anyone know or worked with them?

I'll keep you updated as the saga unfolds.

 

Just looked at that link. 280 lbs is awfully heavy for a generator head.

I have a 7.5 kW gas generator and the engine and generator and fuel tank together does not even come close to to 280.

The other weird thing I see is the shaft is likewise large at 42 mm. Way overbuilt for a 10 kW gen head IMO.

 

Those chinese "ST" gen heads are heavy, 1st generation technology DC Field Forcing, Brush type generators.
Your burnt one is likely the newer technology brushless, capacitor type excitation.

I'll guess that your burnt gen head is a single bearing type meant to flange right up to the Kubota diesel engine block & flywheel. All those ST's that I've seen are 2 bearing types.

I recommend "THE" fountainsource for generator info on the web which is http://www.smokstak.com/forum/
There are some extremely knowledgeable guys on there.
I'll bet there's at least one guy on there that knows your generator inside-and-out.

Good luck on your quest.

 

Thanks guys. I'll check it out.

I don't know what just the generator head on mine weighs but the whole unit is supposed to weigh around 475#.

I did find out what probably caused the problem with mine. I took the end cover off and found several large (1/2"x3/4"x1-1/2") chunks of epoxy or something similar that had come loose from the internal windings and wedged between the windings and the frame. I'm assuming that those damaged the windings causing my problem.

 

Ebay shipping for that ST beast... $110.00,

 

Hello, 12valve@heart. Probably wanted to disregard this thread coz it was posted months long. Sorry for bringing this thread up anyways. But i guess you haven't solved the issue yet. Well, i had my rotor replaced with a rebuilt one and i found shop in OK. The name of that shop was A & J Garage. Here's the contact info.

1617 Hampton Dr,
Oklahoma City, OK, 73115
405-737-5935

im sure they could help you. Just contact tim and told him you was refered by andrew cutchere. if not im sure he would be able to point you in the right direction.

 

Hey, thanks for the info Andrew.

Actually, I did resolve it but I neglected to post an update. It was a very long story but the short version is that I had the rotor and stator tested at an electric motor rewind shop and they found no problems so I reassembled the generator and wired it according to factory instructions and it worked fine and has for about 250 hours now. It turns out that the shop that I took it to were ID 10 Ts and not only miswired the new regulator causing the problem but then misdiagnosed the problem. I did the research and put it all back together and in on my own.