On Thu, 03 Mar 2011 19:20:41 -0500, Ned Simmons
wrote:

On Thu, 03 Mar 2011 18:55:04 -0500, Bob Engelhardt
wrote:

Wild_Bill wrote:
... use a KB or similar
DC controller that will provide excellent speed regulation (won't slow
down with varying loads..
...

I have a KB controller on a treadmill motor that drives my belt grinder.
I get a lot of slow-down on heavy loads. For real speed regulation,
use tach feedback and a servo amp.

Aren't treadmill motors series wound? If so, I'm not surprised the KB
controller doesn't work very well. Their speed regulation is quite
good with PM and shunt wound motors, as long as the proper HP resistor
is installed.
Some are series, some are shunt, and the VAST majority are PM.