PM 3520 A or B lathe owners VFD Drive question

[Thomas Hotchkin]

Any Powermatic 3520 A or B model owners that have replaced there VFD drive. Did you purchase a replacement from Powermatic or a VFD distributor and was there a need to reprogram the new VFD for correct operation? The reason I am asking is there is a $200.00 difference in price from PM and a VFD drive supplier. Thanks for any help Tom

[Eric Holmquist]

Generally you are going to do some level of programming on the VFD. It will have default min / max Hz that may differ from the PM one. It will probably default to 208V 3 phase output, not sure that's what the motor you have is. Then there are the controls. You will have to program the VFD to use the Fwd/Rev switch and speed knob, by default it will most likely want to control speed and direction from it's built in buttons / knob. Programming a VFD on test equipment at work for the first time took very little time at all.

The thing that is hardest to gauge is the gains that will give you decent acceleration and deceleration while giving you smooth operation. The defaults may be ok, but most industrial VFD applications do not vary in speed as much as we turners use so that might need tweaking.

[Reed Gray]

The ones from PM would probably be pre set to their settings. With a new one, you would have to program it, which probably could be done with a tech from the home company. Braking time, minimum and maximum speed settings, and torque can be varied a lot. I preferred the settings on the A model where maximum speed on the low range was 1500, and minimum speed was almost 0, which is great for sanding warped bowls.

robo hippy