Re: counter shaft

[Lee Hart <leeahart@earthlink.net>]

Michael A Perry wrote:
> Advanced DC motor, driving Gates Polychain [belt] into a countershaft
> @ about 2:1 ratio, stepped down another 4:1 to the rear wheel...
> countershaft has a pulley at each end, supported by 3 bearings...
> After a 5 mile drive, I noticed all 3 bearings are warm to the touch

Heat is a good indicator of inefficiency. Are they sleeve or ball
bearings? There is quite a bit of side loading, so I think you'd want
ball bearings.

Why 3 bearings? It would be devilishly difficult to keep them all
aligned. If they are not absolutely concentric, there would be extra
losses from excess side loading and shaft flexing.

When you jack up the rear wheel, and spin it up to speed, how quickly
does it coast back down to a stop? I would expect it to take 5-10
seconds to coast down from full speed. Or another way to look at it; how
much power does the motor use to run the back wheel at speed in the air?
I would expect full speed to take 10-20% of the power that it would take
to drive at that speed. (PS -- be CAREFUL running the car with the wheel
in the air! Make absolutely sure it can't vibrate or fall off the
supports!)
--
Lee A. Hart                     Ring the bells that you can ring
4209 France Ave. N.             Forget the perfect offering
Robbinsdale, MN 55422 USA       There is a crack in everything
phone (612) 533-3226            That's how the light gets in
leeahart@earthlink.net                  Leonard Cohen