Spotlight on Light Plants

| August/September 2002

We're doing something a bit different this month, namely, introducing readers to the Sparks & Arcs bulletin board.

The Sparks & Arcs conversational board can be found on the internet at, and it's one of several bulletin boards on EnginAds, where you'll also find the SmokStak bulletin board.

Unlike SmokStak, which deals mostly with general engine questions and issues, the Sparks & Arcs board is specifically for antique gasoline generator and home light plant collectors, a place for these collectors to discuss and share their restoration and collecting experiences. So without further ado, we present this discussion from the Sparks & Arcs bulletin board.

Do any of you guys have a schematic, or maybe a manual, for a Universal Model D 3KW generator, circa 1918? Also, who can do a good job of re-varnishing and baking the windings? This unit appears to be in good condition, but the wrapping is dried out and cracked and I don't want to risk damaging anything when I run the engine. It hasn't been run since the 1920s. I'm assuming the original wire was covered with either cotton wrap or varnish, shellac, etc., and that the insulation is still intact. The coils are covered with what appears to be cloth tape and I haven't removed any of the covering. Should the complete coil assembly be soaked and baked as is, or is it best to rewind the coils with newer wire? - Harvey

Spray varnish may not be the way you want to go with this project. Originally, the machine was soaked in a tank of varnish for several hours, drip dried and then baked for final drying. Motor rewind shops still do it that way. The varnish needs to penetrate the open spaces to be most effective and to adhere all the winding parts together. Spray varnish is intended for touchup purposes only. - Franz

Why varnish instead of shellac? - Harry