Diesel welder gen problem

Sometimes it welds.
Welder cycles on and off like a load is applied but there is no load.
Why would the gen set load and unload. It will only weld while it's "loaded"
The throttle is fixed and the engine is stable, it's the gen set that is
coming and going. Any ideas? Old generac with Kubota engine. 5,500 w
Reply to
Mike
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Mike,
Is the RPM staying constant or is it "hunting-or-surging"? If not, and it's stable and staying at a constant speed the brushes may be shot or on the way out. I just replaced mine in a Miller Legend just for good measure and I noticed a surprising increase in the weld power. I also cleaned the commutator, rotor-gizmo with abrasive cloth and it made a huge difference. (Five bucks total cost) If the engine is bouncing all over the place I don't know if your unit has one but there is a solenoid on mine attached to the governor linkage that affects the engine drive speed when set to the "weld" or "auto detect" setting. Maybe take a look at the circuit and hardware. My manual indicates that the springs have a short service life. If it's weak, the governor could easily be getting out of whack. I just was not too clear if you have stable engine performance or just electrical fluxuation. I have only fixed my Miller and I rebuilt a Pipe-Liner for a friend a week ago, I'm no expert. I'm just tossing out what I have to offer.
Respects,
Rob
Fraser Competition Engines Chicago, IL.
Reply to
RDF
Thanks for the reply. I fixed the throttle and it's not the engine. The generator is charging and then not charging. Almost in a timed interval of about 4 minutes or so. But there is no load applied. When it's "charging" it will weld. Welder has set up for five years or so. You can actually here the engine load up a little when it goes into the "charging" mode. I'm a diesel injection specialist and it's not the pump or engine. Would the brushes come and go?
Reply to
Mike
Oh yea, the brushes are even commented in my manual as a high wear/attrition part set. I would assume that pretty much all units are built around the same technology (As I said earlier, I'm no expert at all. More like a dangerous amateur). I'd just drop a few bucks on the brush set and see if that fixes it. I would think that if the coil or windings were bad it would be a totally dead situation and not intermittent. But, then again, I am not all that sure of what goes on inside them. Just the basics really.
Rob
Fraser Competition Engines Chicago, IL.
Reply to
RDF
Is there a regulator on the generator ? it might over-rev with no load...
There might be an internal switch that doesn't switch nicely.
Martin Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member
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Mike wrote:
Reply to
Martin H. Eastburn
Mike,
Any luck yet? Marty is on the same page as my original comment to your post. Just wondering how it was going..
Rob
Fraser Competition Engines Chicago, IL.
> Is there a regulator on the generator ? it might over-rev with no load... > > There might be an internal switch that doesn't switch nicely. > > Martin > Martin H. Eastburn > @ home at Lions' Lair with our computer lionslair at consolidated dot net > NRA LOH & Endowment Member > NRA Second Amendment Task Force Charter Founder > IHMSA and NRA Metallic Silhouette maker & member >
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> > > Mike wrote: >> Thanks for the reply. I fixed the throttle and it's not the engine. The >> generator is charging and then not charging. Almost in a timed interval >> of >> about 4 minutes or so. But there is no load applied. When it's >> "charging" >> it will weld. Welder has set up for five years or so. >> You can actually here the engine load up a little when it goes into the >> "charging" mode. >> I'm a diesel injection specialist and it's not the pump or engine. Would >> the >> brushes come and go? >> >>
>>>Mike, >>> >>> Is the RPM staying constant or is it "hunting-or-surging"? If not, >>> and >>>it's stable and staying at a constant speed the brushes may be shot or on >>>the way out. I just replaced mine in a Miller Legend just for good >>>measure >>>and I noticed a surprising increase in the weld power. I also cleaned the >>>commutator, rotor-gizmo with abrasive cloth and it made a huge >>>difference. >>>(Five bucks total cost) If the engine is bouncing all over the place I >>>don't know if your unit has one but there is a solenoid on mine attached >> >> to >> >>>the governor linkage that affects the engine drive speed when set to the >>>"weld" or "auto detect" setting. Maybe take a look at the circuit and >>>hardware. My manual indicates that the springs have a short service life. >> >> If >> >>>it's weak, the governor could easily be getting out of whack. I just was >> >> not >> >>>too clear if you have stable engine performance or just electrical >>>fluxuation. I have only fixed my Miller and I rebuilt a Pipe-Liner for a >>>friend a week ago, I'm no expert. I'm just tossing out what I have to >> >> offer. >> >>> Respects, >>> >>> Rob >>> >>> >>>Fraser Competition Engines >>>Chicago, IL. >>>
>>> >>>>Sometimes it welds. >>>>Welder cycles on and off like a load is applied but there is no load. >>>>Why would the gen set load and unload. It will only weld while it's >>>>"loaded" >>>>The throttle is fixed and the engine is stable, it's the gen set that is >>>>coming and going. Any ideas? Old generac with Kubota engine. 5,500 w >>>> >>>> >>> >>> >> >> > >
Reply to
RDF

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