On Fri, 07 Oct 2016 23:07:43 -0400, wrote:

On Fri, 7 Oct 2016 20:52:54 -0500, "Terry Coombs"
wrote:

I picked up a rock tumbler power unit today at a yard sale with the
thought of using it to spin a ball mill for other compounds . Problem is
that I think it might spin too fast , and I may need to slow it down . I can
use smaller rollers on the shafts (2 , parallel and both turned by a chain
drive) to slow it some , but might need to lower the input RPM's . Currently
has a 1/3 hp split phase motor turning at 1725 - is there any way to speed
control that motor short of changing the input frequency ? Other choices may
be a smaller motor sprocket , or maybe an inline (planetary?) gear reduction
unit or v belt and jackshaft arrangement . Could also change out to a
universal or DC motor and appropriate control system , or use a 3 speed fan
motor I have on hand . But speed control of the current motor would be the
easiest and cheapest ...
VFD.

Not if its a single phase motor, and finding small 3ph motors under
1/2 hp can be problematic.

A DC motor and drive may be his easiest and likely cheapest bet. There
are surplus places that sell both as sets for under $50, last time I
went looking for one for another application.


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