7 month old 3520B

[Sam Beagle]

I'm so disgusted. I turned my lathe on and "BOOM" something popped in the VFD. So I turned the lathe off and it wouldn't start spinning. So I hand spun the bowl and started it and it ran. So I talked to PM and they are sending me a VFD. But my question is, did I do any damage to the motor and what should I be looking for if I did. Thanks. Sam

[Doug Rasmussen]

Probably no damage to the motor itself. 3 phase motors tend to be somewhat "bullet proof". VFD's aren't quite so bullet proof though.

This is the second wood lathe VFD problem I've read about recently on a wood turning forum. The other one was a pre-programmed unit with no keypad or read out. Not having a keypad could be either a cost saving issue or to prevent users from messing with the recommended settings or both.

[Doug Ladendorf]

Sorry to hear about your trouble. One of the benefits of a VFD is that they provide a bit of motor protection. As Doug R says three phase motors have less to go wrong since they have no capacitor or centrifugal switch. Good luck with the fix, I suspect it will be OK.

Doug

[Alan Heffernan]

Agree that it is just VFD issue. A new one will solve your problem.

BTW, if you're handy with a good multimeter, soldering iron, etc., save the old one and repair it. Do some searching and you will find which components usually let go. Do some testing, find the bad component and replace it.

[John K Jordan]

save the old one and repair it. Do some searching and you will find which components usually let go. Do some testing, find the bad component and replace it.

I agree. I know a guy who did that and how has a spare on his shelf.

Sam, you can look up Doc Green's website for good info on debugging the PM lathe electrical.

Also, I read elsewhere that the big capacitors in the VFD can fail and cause the problem. The sound you heard may be consistent with that. It's an easy fix.

Replacement is a no-brainer, just takes a couple of screwdrivers and maybe making a photograph or diagram to get the wires back on correctly.

The VFD on one of my Jet 1642 lathes quit after about 12-13 years. A factory replacement was so expensive I bought and programmed a much cheaper VFD to fix it.

JKJ

[Brice Rogers]

I agree with John and Alan on trying to repair the VFD. I've found that often times when sometime catastrophically stops (that is with a loud POP and perhaps some smoke) that it is pretty easy to find the failed component just by looking at the circuit board. Look for a burn mark, a "puffy" capacitor, something with an obvious crack, etc. Also, check out the circuit board traces with a bright light and magnifying glass to look for any vaporized conductors.

(Of course, make sure to unplug the electricity before you do this)

[John K Jordan]

You can sometimes locate a burned component by smell too.

Over the years I have found a significant percentage of failed electronics was due to cold solder joints. In one single week I fixed air conditioners on two of our vehicles, both due to cold solder joints on the control boards. I've found them on one of my midi synthesizers, computer boards, in appliances, and more. A magnifier and bright light can help but it usually doesn't take long to simply remelt every solder connection. (at least those not done by a wave soldering machine which seem bulletproof.)\

Another thing that is fairly common is a microscopic broken pc board trace which sometimes shows up after a board heats up. If I can't find anything with the magnifier I start with the can of freeze spray. That sometimes works to find the bad solder joints since the temperature may shock the joint into working or not working.

Years ago a lot of things came with a circuit diagram. With the diagram, meter, and possibly the oscilloscope things were usually easy to fix. Anyone know where to get a circuit diagram for the Delta VFD used on a Jet 1642? I spent a few hours on it with the scope before I gave up.

FWIW, this is my favorite magnifier for examining everything from electronics, wood structure, feathers, bugs, splinters... Inexpensive, good 10x lens, measuring scale, and three bright LEDs, uses two AA batteries.
https://www.amazon.com/gp/product/B00CMDIOBK

JKJ