On Thu, 14 Apr 2005 17:51:30 -0400, "Proctologically Violated©®"
wrote:

Awl--

I acquired this incredible Engleberg 4" pedestal belt sander, but w/ shot
motor, shot driveshaft, on which I've posted elsewhere.

The replacement motor is proving to be a problem. Direct replacment is
possible, but expensive. (Cast iron finned, 1700 rpm, 143 frame).
Rewinding is expensive.

But I've been finding possible motors, but w/ 3450 rpm, 3 ph, 1 hp.

Would this motor on a VFD be a viable solution? As a direct drive unit, I
don't have the luxury of mixing pulley ratios, so would torque be a problem,
at dialed-down speeds--actually, 50% speed?
Would the higher speeds be any advantage for some materials??

What are people paying for these sized VFDs?
TIA!
----------------------------
Mr. P.V.'d
formerly Droll Troll

I'm no expert by any means, but when looking into this solution for
replacing a DC spindle drive on a CNC lathe with an AC drive the big
problem would be the loss of power at lower rpm. I.E. the slower the
motor went, while maintaining constant torque, the lower the HP
delivered to the spindle. Now, VFDs have progressed much since then.
It may be that the torque will be doubled with the halved RPM. If
that's so then then it's all good, just provide enough cooling with an
extra fan. But, if the torque remains the same, HP will be half. If
you need the full 1 HP at 1750 rpm then maybe a two HP 3 ph motor
would be best.
ERS