VFD on Powermatic 3520B

[Brad Winesett]

I'm going to look at a used Powermatic 3520B this week. I have a picture of the VFD and just wanted to know if this particular VFD was problematic at all.

Also, what is the knob used for? Does the knob only function while in programming mode? If not, should it really be set on max as shown in the picture.

 

[Dave Landers]

I have a 3520B and a Jet 1642, both have Delta VFDs.
I really like my 3520B - a good, solid lathe.
I believe the knob is there for frequency (speed) control, but PM has wired that to the knob on the front panel of the lathe. So the knob on the VFD is basically just decoration. The only thing I've ever messed with on the VFD panel is the reset button - in those rare times I got way too aggressive on a big bowl and the VFD overload tripped.

 

[Tom De Winter]

Our Club has at least a half dozen lathes with this VFD. I’m new to the group but think they have been trouble free with one exception.

I’ve been working on this drive and yesterday ordered a new one. I found some of the components are obsolete and very hard to source. I wonder how much longer replacements will be available.

Even considering that I would not be afraid of a used lathe with this drive. The drive could be replaced with a current model if it became necessary.

 

[Dean Center]

I would say the consensus is that the Delta VFD was not top of the line, but served most folks well for a long time. Sometimes it didn't but mostly it was fine. If it needs to be replaced, satisfactory new ones can be obtained for $200-300. (as of a year ago--not sure what's happened since the coronavirus came along)

 

[john lucas]

One of the main reasons I purchased my Powermatic 17 years ago was because virtually everything on that lathe can be replace by aftermarket pieces or built or repaired by a machinist. I expect this lathe to last a lifetime (and I plan on living a lot longer). The VFD is one of those aftermarket replaceable items. I had owned 2 other Nova lathes and loved them but the new Nova DVR scared me with proprietary parts that could only be replaced by the factory. That's fine as long as they carry the parts but what happens if they shut down. So I purchased the Powermatic and love it.

 

[Mike Johnson]

John makes a very good point on available repair parts for a lathe, the market is what you might call saturated with a large number of make and models. Seems like every time there is a hiccup in the economy for any length of time manufacturers go through consolidations and trimming product offerings to cut overhead costs. One area that gets hit hard are inventory levels and support of obsolete equipment, this trend usually increases new model sales over time. VFD's are the one component that gets obsoleted very quickly compared to other components that are used to manufacture lathes with. By using a generic VFD available in the market you don't need to deal with proprietary programs and passwords that some lathe manufacturers use. The motor should be a commonly used 3ph voltage and industry standard NEMA mounting plate or feet so you can easily replace with an off the shelf motor made by the major manufacturers. If a special design motor is used you will some day have a problem getting a new one and having a motor rewound and new bearings installed can get expensive. .