Re: Running DC motors at higher speed

["Chuck Hursch" <chursch@yahoo.com>]

I always get something out of a Lee Hart post - they are written
in such a way that I have a shot at understanding and retaining
the fundamentals.  Thanks,  Lee,  I appreciate you taking the
time to write your posts!  I and my EV friends get a lot out of
them.

Chuck Hursch
Larkspur, CA

----- Original Message -----
From: Lee Hart <leeahart@earthlink.net>
To: <ev@listproc.sjsu.edu>
Sent: Thursday, May 30, 2002 2:24 PM
Subject: Re: Running DC motors at higher speed


> jcmassey@netspace.net.au wrote:
> > If a motor has a rating of so many horsepower at such a
voltage and
> > RPM, what is the effect of increasing voltage?
>
> First, what type of motor are you talking about? I'll assume a
> brush-type series DC motor, since that is the most common type.
The
> results would also apply to a shunt or PM DC motor if you don't
change
> the current.
>
> > Since (correct me if I'm wrong) the heating of a motor is
purely from
> > amps, we can increase the voltage, but to keep the amps
unchanged, we
> > need to run at a higher speed.
>
> The main losses in a motor are resistance, friction, windage,
and core.
>
[snip]