Hi,
I have a lathe spindle with 8 in. chuck that is run with a 5HP Reliance
DC Motor and Reliance DC Drive.
I just cannot get much power out of it at low RPM. Was trying to turn
8in OD steel, at approx. 200 -250 RPM with .005 in. cut. It didn't work,
it just stalled.
When I run it at low RPM the chuck rotation is movable, not firm.
I can take a hold of the chuck and hold it and move it back and forth as
it rotates.
It also is more noisy at low RPM.
This lathe is a Linuxcnc retrofit with J Elson's Universal PWM
Controller and DAC Spindle control.
The DC drive has tachometer feedback from the motor.
I have tried numerous times to adjust, tune the drive, without success.
I also tried closed loop control from the spindle encoder within LCNC,
also no success.
So here come the questions:
Should I keep trying to get this DC Drive working or would it be better
to switch to AC Variable Frequency Drive?
If I would switch to AC VFD would 5HP AC Motor be sufficient size for
existing 1:1 ratio double v belt to drive 8" spindle chuck?
What torque at low RPM can I expect for this 5HP DC motor? am I
expecting to much from it?
Would there be a better drive option for the existing DC motor?
Any recommendations?
Thanks,
--
Earl Weaver
Email: [email protected] <mailto:[email protected]>
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