Ralph & Elaine Vogan wrote:
For 2 years I have been using a Craftsmen snow thrower that I converted to electric. I used a 3 hp. series wound 85 amp motor at 3000 rpm. out of an industrial cart. It would peg the load meter at startup and it would stay pegged while running. This summer I got an old E20 for parts (bad rusted threw frame). I swapped the E20 drive motor with the series motor and now it pegs the meter on startup then quickly drops to about 1/2 of the green on the meter. The speed of the snow thrower is slower (I'm guessing about 900 rpm). I think that is because the pulley is about 1/2 inch smaller. now all we need is some snow to see how well it works. Both motors have good bearings and brushes so the difference must be just the design of the motors. Both are G.E.s. Maybe the high current drain of the series motor was causing my battery problem?
That is really interesting, and I'd love to see some pictures to see how it all works. I kind of like the Elec-trak's single stage thrower; if you paint the throat with POR15 it almost never clogs and it can eat an iceberg.
The reason it might have been pegging is that series motors want to spin at a particular speed for voltage and will do anything to get there. Shunt motors spin at a more regulated speed, but it's probably slower. The motor on my thrower is a series one, but it's matched to the proper speed for the rotor. When I hit serious snow it pulls to max power. Same with the tiller actually; it either goes at a specific tine speed or it's doing everything to get there.
Chris
Merry Christmas Ralph Vogan ralphgv talkamerica net ------------------------------------------------------------------------ _______________________________________________ Elec-trak mailing list Elec-trak cosmos phy tufts edu https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak