Re: AC Motor Speed Control

--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@...>
wrote:

>
> GS2 VFD from automationdirect.com and a 3 phase spindle motor.

Softwares like Mach3 can control it with an analogue signal.

>
> Ron

That begs the question of motor size.

If hp is dependant on speed, and torque is constant, should one use
a larger motor so it has more power at lower speeds ?

I can see some huge benifits from variable speed, but at the same
time, it would appear that one might not get all the way from 1% to
100% speed and have enough power for all machining in-between.

And, yes, a simple high/low belt change would make that less of a
problem.

The reason I ask is that I put a treadmill motor and power
controller on my 9" lathe and notice it has some weak spots at lower
speeds.

Dave