Here's a link to motor nameplate, drive info etc.
https://www.dropbox.com/sh/8k6ss8tfbfl4muj/AACFFFxQLOsuvu04vPmuK21Ta?dl=0
Would there be a benefit for me to change the motor pulley to a smaller
size?
On 7/26/2021 8:04 PM, Gene Heskett wrote:
On Monday 26 July 2021 18:11:45 Earl Weaver wrote:
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.
All of the above and below description, would seem to fit where the DC
supply is duff. Do you have ny docs on it, and test gear like a scope
and dvm?
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?
Can you copy the motors nameplate data to us? And do you have a dvm with
an amps range that includes the amperage listed on the nameplate as FLA?
That stands for "Full Load Amps" but many DC motors can be pushed harder
than that, up to twice that if its starting a heavy load as it will drop
a lot as it reaches the requested speed in a second or so.
Thanks,
Cheers, Gene Heskett
**Earl Weaver
Email: [email protected] <mailto:[email protected]>
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