Spindle speed question

[denmanmarine]

Hi all,

I have a PRS Alpha with the 5hp 3ph Colombo spindle. Can anyone advise what the slowest RPM you can get this to run at? Can't seem to get it below 11,000.

TIA

AD

[kubotaman]

When I had mine I could get it down to 4000 RPM without problems. Don't know if I could have got it any lower.

[bleeth]

11k is way over it's lower threshold.
In fact, when you first start it up you should run it at 4-6 k for a few minutes as part of the warm-up sequence.

So are you meaning that it just won't run slower than 11k or that when running under 11k there is some issue in cutting at lower speed?

[Brady Watson]

If you are using SB spindle control, I believe the lower limit is 5,000 RPM. If you run the VFD under manual control, you can run it down to 60 RPM. 6,000 is about the lowest useful speed for this spindle. Any lower than that and it doesn't have any torque. It's like starting out in 3rd gear.

-B