This is guaranteed to play havoc with the servo tuning.

I'll discover this for myself first hand then.

I still don't understand why you can't simply limit
the motor velocity in your software.

Me neither, it's just not going to be the first option tried. Prefer a
hardware solution.

AMC makes some that will operate as low as 16V

Thanks!

"Ned Simmons" wrote in message
...
In article 2Alzd.14978$rL3.7321@trnddc03, says...
The resistor is reducing the voltage and hence the speed of the motor,
preventing a 5000 RPM motor from spinning at over 10000 RPM leading to
bearing, commutation, brush and possible winding (excess centrifugal
force)
problems. Yes, I can run the motor at 24V and 50% duty cycle and do the
same
thing but there may be other issues.

Using 10 rectifier diodes in series I see only a .8V variation at the
motor
(13.6V - 14.4V) with the PS at 23V and under the same load conditions
mentioned earlier. Yes, I'll need 20 for both directions but they're
cheap.
Bottom line....G320 and 12V motor should be feasible one way or another
at
24V. Just waiting on Gecko's take on it and still looking for a 12V
compatible drive.

The resistor is a bad idea, but the diodes are a *really bad* idea. At
least the resistor is a linear circuit element. The diodes are going to
introduce a stepped voltage drop between the amp and motor. This is
guaranteed to play havoc with the servo tuning.

I still don't understand why you can't simply limit the motor velocity
in your software. The amp is isn't going to deliver any more voltage
than what is required to drive the motor at a given speed.

Re low voltage amps, AMC makes some that will operate as low as 16V, but
I don't recall if they're for brush or brushless motors, and I'm sure
they'll be much more expensive than the Gecko drives.

Ned Simmons