Denford Software & Machines

We are running a 1992 vintage TRIAC PC 3-axis machine that, in general, we are quite happy with. Our students have been learning a great deal and the system has been quite reliable for many years. However, we recently measured the spindle speed with a non-contact tachometer and found the actual speed to be much slower than the commanded speed, by a factor of about 2.7. (Please see attached file for data.) We would very much like to operate the spindle at the commanded speeds; at present our spindle tops out at about 1800 rpm. We also measured the spindle speed some years ago and found similar results, so I believe that our spindle has never operated at the commanded speed. Could you please put us in touch with your technical support, so that we might be able to determine if we can operate the spindle at the commanded speed?



We are running VR Milling version 2.31.3.951, and I believe that our system has the Lenze 530 DC spindle drives.

Has this machine been upgraded from DOS then ?

I'm sure there is a voltage change needed for the override pots, when upgrading. Is the spindle override pot changing properly, or at least able to show 100% in the software ?

I guess that this machine has been upgraded from dos to VR Milling at some stage.

1. Check that the spindle speed overide pot is set to 100%. If the machine has been updated to a next move card you may find that there is only a small sweep on the pot where the overide is effected. (If this occurs a small electrical mod can be performed to rectify).

2. The spindle speeds are set up via a pot on the "Custom Card" & the "Max Speed" pot on the spindle drive board.

3. The Custom card is the second card in from the left in the rack. If you look at the back right near the bottom you will see a small blue pot with the screw poinintg forward. Use this screw to adjust the bottom speed of the motor.

4. The Max Speed pot on the drive can then be used to set the top speed.

5. You may need to perform the above 2 steps a couple of times to bring the min & max together.

We were able to locate and adjust the minimum pot so that 250 RPM on the PC corresponded to 250 RPM on the spindle.

However, we could not locate the Max Speed pot. Which board is this located on? We think from your wording that it is on the Spindle Drive board, but we're not sure which board this is.

The first adjustment went great, thanks for the help.

If its what I think it is, the spindle board is the 2nd one from the left.
The main baldor card with the 7-segment display has a ribbon cable going from it, to the spindle card - so the spindle card will be the one next to the baldor control card.

That is the board that we adjusted the Min. speed with. But we only found a single (blue) potentiometer on that board.

Should we check again for another pot?