On Sun, 09 Oct 2016 13:48:43 -0400, wrote:

On Sun, 09 Oct 2016 08:23:49 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

fired this volley in
m:

I THINK he was talking about remoting the speed pot on the VFD. A
relatively simple 3 conductor cable on the "voltage devider".
Possible for sure, but a bit of a pain.

I never read any indications that he was talking about multi-phase
motors. OF COURSE it can be done that way, but all the discussion here
was about chopper-controlled single-phase induction motors.


Which STILL uses a sped control pot There ARE variable frequency
single phase drives - they just have a narrower speed range and
perhaps a diminished starting torque.

Single phase input..3ph output is quite common.

That sort doesn't particularly like that sort of control _anyway_, unless
they were designed for high-slip operation (like, say, ceiling fan
motors).

But, again: A properly designed ball mill requires NO speed control over
a fairly wide range of jar sizes.

LLoyd
Because it is basically the linear speed of the inside surface of the
jar that is critical.

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