[clapper33]

Need some help troubleshooting a spindle speed issue.
Just purchased and moved machine, seems like low hours for the year ('94 vmc 15 w/rigid tap). It was powered off for a while (over a year, I'd guess). Everything seems to be working other then the spindle issue.
When I command the spindle speed of say 750 rpm, it spins almost 2500 rpm according to the baldor drive (see pics). I read there is a way to tell the drive to spin up the motor to see if the spindle control card is an issue, but not sure how to do that.
Would I need to re enter settings into the drive being powered off that long?
It's being powered by a 20hp RPC. It's pretty balanced, 236/239/242 and transformer is tapped for 240. I forgot to check the legs to ground so don't have those numbers. I did try and swap L1 / L3 just to see if the phase would be an issue, no difference. Currently L1&L2 have the regular power and L3 has the generated leg. Thank you in advance!

[rwskinner]

I don't know anything about a VMC15 but most of the Fadals have a High Low idler system. Do you know if it's working?
S750.1 M3 will command 750 RPM in low gear. S750.2 M3 will be 750 in high gear.

You can use the codes, “S.1” and “S.2” tochange from High to Low gear. If you have the cover off the spindle you should see the tensioners move and usually hear them.
If the air lines for the 2 tensioners get mixed up or crossed, very weird speeds will occur for sure. I know

Some of the older smaller Fadals don't have the Lo/Hi tensioners and you had to manually change the belts. I believe those had 6 individual belts.

[clapper33]

I don't know anything about a VMC15 but most of the Fadals have a High Low idler system. Do you know if it's working?
S750.1 M3 will command 750 RPM in low gear. S750.2 M3 will be 750 in high gear.

You can use the codes, “S.1” and “S.2” tochange from High to Low gear. If you have the cover off the spindle you should see the tensioners move and usually hear them.
If the air lines for the 2 tensioners get mixed up or crossed, very weird speeds will occur for sure. I know

Some of the older smaller Fadals don't have the Lo/Hi tensioners and you had to manually change the belts. I believe those had 6 individual belts.

Ok, think I've got it! Parameters were set wrong. It was set for a 10k spindle and it has a 7500 spindle. Just one belt, no hi/low option like 4020's

[Andrea9401]

When the CNC lathe operates in Constand Surface Speed ​​mode, the spindle speed is directly related to the current part diameter. The smaller the workpiece diameter, the higher the spindle speed. So the question is: what happens if the diameter reaches zero? It seems impossible to program with zero diameters, but at least two cases consider this possibility.

In the first case, zero diameters are programmed for all centerline operations. All drilling operations, center drilling, tapping, etc. are programmed with zero diameters (XO). These operations are always programmed in direct r/min mode, using the G97 instruction. In G97 mode, spindle speed is controlled directly, and r/min does not change.
Drift Hunters

[servtech]

When the CNC lathe operates in Constand Surface Speed ??mode, the spindle speed is directly related to the current part diameter. The smaller the workpiece diameter, the higher the spindle speed. So the question is: what happens if the diameter reaches zero? It seems impossible to program with zero diameters, but at least two cases consider this possibility.

In the first case, zero diameters are programmed for all centerline operations. All drilling operations, center drilling, tapping, etc. are programmed with zero diameters (XO). These operations are always programmed in direct r/min mode, using the G97 instruction. In G97 mode, spindle speed is controlled directly, and r/min does not change.
Drift Hunters

You set a spindle speed max variable for G96 for safety reasons. You may have a chuck with 5000rpm limit, use that or lower if for example your spindle can achieve 8000rpm. Ie. G96 P3000 Q5000 min and max on some controls. Check your op. manual.

Exceeding safe speeds can cause workpieces to fly out of the chuck as it loses clamping power at high speed. You can set minimum speeds too, to ensure spindle doesn't stall on biggest diameter or rapid return.