• May 2025 Turning Challenge: Long Neck Hollowform! (click here for details)
  • Congratulations to Phil Hamel winner of the April 2025 Turning Challenge (click here for details)
  • Congratulations to Dion Wisniewski for "Basketweave" being selected as Turning of the Week for 12 May, 2025 (click here for details)
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

Powermatic 3520B with bed extension, needs new VFD!

N

Nate Hawkes

Joined
Jul 21, 2008
Messages
143
Likes
1
Location
Staunton, VA
Just trying to see if there's any interest for a Powermatic 3520B that needs a new VFD. Pictures to follow. I've used it to turn hundreds of bowls and boxes, and apparently the VFD shorted out; either a big power surge or a lightning strike. It worked wonderfully until it just wouldn't turn on anymore. The current VFD is disconnected. I attempted a replacement with a used Delta S1 VFD type D and was discouraged when it didn't work as expected. I've decided on an upgrade to either a 4224 or an American Beauty, or I'd get a brand new VFD and figure it out. The lathe will come with 2 banjos, a 12" tool rest, the 18" bed extension, a powermatic faceplate, live center, and a knockout bar. I have a simple ballast box made of 3/4" plywood to hold 8 bags of sand to weight down the lathe and absorb vibration when turning very heavy out of balance natural edge pieces. I'll throw in if you're interested. Located in Staunton, VA.

$1500 firm.

I have had a couple back surgeries and can't help with the loading/unloading. You can pull a box truck up to the garage door for loading.
 
Jonathan Silwones said:
is it not possible to get an OEM VFD?
Click to expand...
The OEM VFD has been discontinued, and their new replacement doesn't work without a complete rewire of all the internal wiring. It's also $1000 and parameters cannot be changed by the owner. They've redone it so that there's no control panel without a computer interface.
 
Darryl Fective said:
It's possible, but there are better options at about a third of the cost.
Click to expand...
I wish it were possible. I actually bought and ordered a new one from powermatic, but was unhappy with not being able to go in and change settings. They also assured me it was a plug and play, and it was not. None of the wiring was long enough, and the enclosure was far too large to fit on the headstock. I have no idea how they expect people to be able to wire it up. I was pretty disappointed in their customer service. They did accept the return and gave me a refund, but I'm without a working VFD.

After the replacement from Powermatic, I tried wired up a used delta S1 type Dmodel, but the potentiometer didn't work, the RPM gauge didn't work, and it didn't have a brake resistor. I'm sure that a different VFD would work fine, but I'm not very electrically inclined. Also, I want a lathe with stainless bed ways. I like turning green, sloppy wet wood, which leads to a lot of surface rust on the powermatic.
 
I put a vfd from Amazon on my 1961 Powermatic 90. It was less than $100 and not too difficult to install. Most of the programming was going down a list choosing options. It's all on the manual.
 
Wyatt Holm said:
I put a vfd from Amazon on my 1961 Powermatic 90. It was less than $100 and not too difficult to install. Most of the programming was going down a list choosing options. It's all on the manual.
Click to expand...

Agreed. Way easier to program, and if something happens, cheap to replace. I've put 3 of them into use (with no problems) and have a spare on the shelf.
 
Sounds like an excellent deal, I have one - for me the bed extension is so valuable. I use mine for extra bed length but if not aware, the bed extension can be mounted low on one end and a tool rest extension can be used to turn things much larger than 20" dia.

And programming a VFD is not too difficult. I bought one for about $100 to replace a Delta S1 that died in a 20 year old Jet1642.

JKJ
 
U might try Facebook marketplace, that's where I sold my lathe.....
 
John K Jordan said:
Sounds like an excellent deal, I have one - for me the bed extension is so valuable. I use mine for extra bed length but if not aware, the bed extension can be mounted low on one end and a tool rest extension can be used to turn things much larger than 20" dia.

And programming a VFD is not too difficult. I bought one for about $100 to replace a Delta S1 that died in a 20 year old Jet1642.

JKJ
Click to expand...

John K Jordan said:
Sounds like an excellent deal, I have one - for me the bed extension is so valuable. I use mine for extra bed length but if not aware, the bed extension can be mounted low on one end and a tool rest extension can be used to turn things much larger than 20" dia.

And programming a VFD is not too difficult. I bought one for about $100 to replace a Delta S1 that died in a 20 year old Jet1642.

JKJ
Click to expand...
The problem for me is tracing each wire in the headstock and then putting them into a new VFD. I would need an instruction manual. I love the lathe, but I am all thumbs when it comes to the wiring. I’m more of a “the red wire here, blue wire there” kind of guy.
 
Nate Hawkes said:
The problem for me is tracing each wire in the headstock and then putting them into at new VFD. I would need an instruction manual. I love the lathe, but I am all thumbs when it comes to the wiring. I’m more of a “the red wire here, blue wire there” kind of guy.
Click to expand...

It would be best to find a local person (friend, turning club member?) with some electrical knowledge to avoid potentially dangerous or equipment damaging misconnections. You should be able to get a manual for any VFD you acquire and the manual for the original Delta S1 VFD (available online).

Someone with experience could compare the wiring of the two and sort out what needs to be connected to what.
There will be wires for 220v single phase power in from the wall, 3-phase power out to the motor, braking resistors, and for the low-voltage control circuitry (on/off, direction, speed, etc.) It's been years since I've looked at these so I might be forgetting something.

Look at Doc Green's website article on PM 3520 electrical for an explanation of all this.

Docs info is specific for the original VFD on the Powermatic 3520b and I think does identify the wiring colors. He provides photos and diagrams. Also if the failed VFD is still attached, someone could map out the wiring. Someone with the same lathe and perhaps step through and write down the programming parameters.
Then the VFD will need to be programmed to work with the lathe, specify directions, acceleration/deceleration, etc. This can be quite confusing but there is info on the web and a lot of experience on this and other forums. The VFD supplier may provide some tech help.

I did all this once, not for the PM, but for a Jet 1642. I talked to Doc and Harvey Meyer to reconcile the electrical differences between the two types of lathes. The hardest thing for me at first was decoding the terminology for and understanding the programming parameters to figure out what needed to be set and what could be ignored. (VFDs are general purpose devices and our lathes use only a subset of the features.) This was a long time ago - maybe it's easier these days.e

Once everything is running, some recommend unplugging the when potential lightning is in the area. Power surges are a potential electronics killers.

JKJ
 
I removed the burned out VFD, and tried with a Powermatic replacement, which was not only too big to mount to the lathe, but would have necessitated all new wiring from it to the motor and controls. I was pretty annoyed with PM customer service. So I obtained a supposedly identical but older VFD; a used S1 Delta VFD. Despite taking pictures of the wiring layout and duplicating it identically to the stock VFD, the speed control wouldn't work, the rpm gauge was blank, and the spool up/down time was several seconds longer than original. I tried changing some of the settings to the PM VFD settings and ended up with the motor not going past a few hundred rpm. I thankfully returned both of them, in hopes of fixing it with a different VFD, but now I just want to get back to turning asap. In the future, if/when it is fixed, I'll be unplugging the lathe after each use. Granted, I got a lot of years of regular, if not heavy use out of it, but didn't do anything to explain it just giving out like it did.
 
Last edited:
Nate Hawkes said:
I got a lot of years of regular, if not heavy use out of it, but didn't do anything to explain it just giving out like it did.
Click to expand...

Note that electronics can die from a number of reasons, a power surge being just one. Components can fail without provocation. It the "old" days, it was a a lot easier to identify and replace failed components but it's getting harder now just finding then. A complete circuit diagram and diagnostic tools are a big help but nearly impossible to find now.

The identical used Delta S1 may have been fine. Things like the maximum motor speed and acceleration/deceleration are simple parameter setting changes - not unusual for an identical VFD that may have been used for another purpose. Hate to say it, but if it was turning the motor on and making it spin was a sign that the VFD was OK, just needed properer programming. Again, that may be simple for someone with experience.

The unworking speed control may be a wiring error or a simple thing like a bad variable resistor - not an uncommon problem.

The LED speed display on the front of the headstock is independent from the VFD and relies on a physical sensor inside the headstock - these sometimes get misaligned. Caution, if I remember (don't have time to check now) that circuit uses a higher voltage than the low-voltage control system.

The mounting issues are not uncommon, often simply requiring drilling and perhaps tapping a few holes in the back of the headstock. You may have to do that for any replacement VFD. Sometimes it's easier to use the existing mounting holes and add an aluminum plate with standoffs to hold the new electronics.
 
You must log in or register to reply here.
Back
Top