CCE said:
I have a 12vdc motor from a power car window and I need to run it at a
higher speed. The load on the motor is pretty low. What can I expect
if I run this motor at 18 or 24 v?
The motor brushes get stressed by high currents; if you start the motor
on higher than normal voltages they'll get stressed more, leading to
faster (sometimes immediate) wear.
The motor bearings get stressed by high speeds; running the motor on a
higher voltage will make it go faster. Whether this causes problems
depends on your bearings.
Iron losses will be higher because the armature windings will be running
at higher than normal frequencies, but if you're loading it lightly this
may not be an issue.
The brushes may bounce if you're going at 2x the normal speed, leading
to quicker (but not immediate) wear and intermittent lower torque.
If you're driving it from something that can limit the current as it
starts up you may be fine, or you may run into brush or bearing
problems. If it's a car window motor chances are that it's running
pretty close to the limits of its design, but you can only tell by
giving it a whirl.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
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