Jet Lathe Phase Converter

[Russell Neyman]

I guess it a case of "out of sight, out of mind" but I've owned my 220-volt Jet 16-42 EVS for several years and just now am wondering about the phase converter that's hidden on the backside of the headstock. There's a control knob and a digital indicator, and frankly I don't have a clue what I should do -- if anything -- with the settings. The machine works fine, so I've never touched it. Funny thing about this is the Owner's Manual doesn't mention a word about it and I can't even find a photo of it. Can anyone teach an old dog new tricks?

Jet phase converter.jpg

[Kevin Jenness]

If it works, don't fix it.

If you can figure out the manufacturer and model you may be able to find programming instructions. Two things that you might possibly want to change are the acceleration/deceleration times and adding a remote stop switch, but you would need to know the specific procedure. Have you asked Jet customer service?

[Richard Casey]

Russell, is it a phase converter or a Variable Frequency Drive? Looks very similar to the one fitted to my Laguna 24/36 that converts the Australian 240 volt single phase to the three phase variable frequency for the motor.
Rgds,
Richard.

[Richard Coers]

It's definitely a VFD. The programming is set to the parameters that Jet provided. You only change it if you want it to stop faster, ramp up faster, etc....

[John K Jordan]

I guess it a case of "out of sight, out of mind" but I've owned my 220-volt Jet 16-42 EVS for several years and just now am wondering about the phase converter that's hidden on the backside of the headstock. There's a control knob and a digital indicator, and frankly I don't have a clue what I should do -- if anything -- with the settings. The machine works fine, so I've never touched it. Funny thing about this is the Owner's Manual doesn't mention a word about it and I can't even find a photo of it. Can anyone teach an old dog new tricks?

Jet phase converter.jpg

[Well, I did it again. I wrote a reply hours ago then got busy with farm stuff and must have forgotten to click the Post button! If you want to stay focused on woodturning don't get horses, mini donkeys, llamas, alpacas, peacocks, guineas, chickens, bees, and many things to maintain around the property including maintaining the equipment that maintains the property...]

A rewrite:
Hey Russell, how old is the dog and how many tricks is he up for?

I have a couple of Jet 1642 lathes and a PM 3520b. They all use the Delta S series VFD which for these lathes converts 110 or 220v single phase power to the 3-phase needed to make the 3-phase motor run, change speed, run in forward and reverse, and control things like acceleration and deceleration ramps when starting and stopping. (I think the VFD Jet and PM use is called the S1 but can't remember.)

About the manual:
My first Jet 1642 came with a printed copy of the VFD manual. If your lathe didn't come with a VFD manual just ask Sir Google for Delta S VFD manual and download a pdf. You will get 185 pages that will make your head ache. Page 1-1 describes how do decode the VFD model number, useful if you want to understand or debug the wiring.

About the knob on the VFD:
- You never have to touch the knob on the VFD.
- If for some reason you want to change a programmed parameter you have to unlock the VFD since Jet and PM both lock it to prevent you from messing things up. An unlock code is easy to find.
- A valid reason to use the knob is to scroll through the parameters and write down the settings. You can't hurt anything doing this. Recording the parameters is handy if the VFD fails and you want to reprogram a replacement. Most are set to defaults so I write down only those settings which are different from the defaults. The VFD manual will explain how to view the parameters.

About the LED display on the VFD:
- It should by default display the current frequency which will change with the speed. When the lathe is powered on but not spinning you should see "F 00"
- If the lathe should fail to start some day check this little display for a possible error code which, if you are lucky, may provide a clue about the problem.
- If the lathe has proper power (and the wiring is good) but the display is blank, you have a problem with the VFD, dead, permanently dead if you are unlucky.

About the VFD itself:
- What you see when you look at the back of the lathe is the front cover of the VFD.
- If curious you can remove the cover screw and open the cover to inspect the wiring and such. High voltage AC is present so it may be wise to first unplug the lathe to prevent death.

Note: some of these VFDs come with a fan for cooling and some don't for some odd reason. Some people add a small fan which may extend the life and save 100s of dollars.

About the internal wiring:
- All the control wiring is low voltage DC, 5v or 10v depending on the VFD. The control wiring goes into the headstock and to the switches and speed control.
- The speed display on the front of the lathe is not controlled by the VFD but by a separate module with a physical sensor inside the headstock. This module is fed AC line voltage from the VFD terminals.

For further reading and troubleshooting:
Doc Green (a fantastic guy) has some excellent articles about many things including the control wiring of a Delta VFD. He describes the wiring used in the PM 3520 but the Jet is very similar except perhaps for the wire colors. He has some good troubleshooting points and more. Look in his list of articles for "PM Electrical": https://www.docgreenwoodturner.com/articles.html

JKJ

[Russell Neyman]

Great info, John. Thanks.