I have a Lincoln "Weldanpower" I bought new 21 years ago for home use. I do some side jobs with it and use it for backup power when we have power outages. The machine has very low hours on it. The Lincoln "Weldanpower" is out of production, replaced by, I think their "Ranger".  The Weldanpower produces 6 Kw of AC power and 225 amps of AC or DC welding current. It is driven by a 1 cylinder Briggs & Stratton I/C engine, with the generator rotor cantilevered on an extended crankshaft.

A few weeks ago, I fired up the Weldanpower to do a few little jobs and then change the oil once it was warmed up. I burned some E 7108, and the generator pickedup load and maintained a smooth arc. I shut the machine down and did the oil change. Fired it backup and got no current for either welding or AC power. Took off the sheet metal and spotted the two slip rings on the generator rotor had cracked through. The slip rings are mounted on an insulated sleeve, on the end of the rotor closest the engine. The slip ring closest to the engine had cracked clean through, borken the soldered connection to the field lead, and was laying loose on the cranksahft extension. The other slip ring was also cracked through, approximately in place on the rotor, with the lead still attached. The fractures were fresh and clean, looking like a seam weld that had opened up.

I called Lincoln Electric and they provided good tech support. A new rotor was no longer available. I asked if the slip rings were made from brass tube stock with a seam weld. Lincoln's engineers said that when those machines were being built,  they used mostly seamelss drawn brass tubing for slip ring material. They did also say that they'd get a lot of brass tubing with a seam weld from time to time. The result was an occasional call from some Lincoln Weldanpower owner in the same predicament as I am.

Lincoln did say they had replacement slip rings available, but I would have to fit them and true them on the rotor.

I had a machine shop, so making slip rings from scratch and fitting/truing them is no big deal. I figure alos that if Lincoln has used that seam-welded tubing i the past, why take a chance that these replacement slip rings will be made of more of it ?

I am an engineer with 37 years experience on pwoerplant work and as an erector, so have some knowledge of what slip ring/brush performance or problems are. Use the wrong material for slip rings, and spark erosion or short brush life results.  For this reason, I am posting here.

My questions to anyone familiar with repairs to welding generator rotors of this type are:

What alloy of brass or bronze should I make the slip rings out of ? What's there looks like a yellow brass, but I am only going on the color of the fresh fracture.

How are the slip rings fixed to the insulating sleeve on the rotor ? Are they shrunk on ?  I would hesitate to use a Lcotite product to bond them on, since the field leads then have to be soldered to slip rings.

A local generator shop is working with me on this repair. Once I get the slip rings on the rotor, they will solder the leads, then pot the rings as well as dipping and baking the rotor with epoxy insulating varnish. I would appreciate any insight or advice that people experienced with this type repair could offer.

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                                                 Joe Michaels