My poor 3520a won't run

[Stephen Saar]

Not sure what happened, but my 3520a just stopped working today:eek:. Well at least it stopped working sometime between a few weeks ago when I last used it, and today. It won't turn on at all, and the display box just says "ou". I googled it, and checked the manual, but didn't come up with anything useful. I did notice that the controller box was warmer than I would have anticipated given that the unit wasn't on. I made sure that it was actually off and not just set to the lowest speed too. I've just unplugged it for now, and I'm hoping that maybe it just over heated some how, but in case that's not it has anyone else seen this error code?

-Stephen

[Ken Fitzgerald]

Stephen....I don't have a manual for the speed controller on that lathe. Could it have be a code of "OV" rather than "OU"? Did you by any chance have a power outage due to a thunderstorm etc? Unplugging it may reset the error. I searched online and couldn't find anything. Good luck!

[Steve Schlumpf]

Stephen - did you find out anything?

[Bob Bergstrom]

The 3520 us notorious for going blank once in a while. Unless you have had a power surge, just unplugging it for a minute will take care of it. It will reset itself. When I do big bowl it can happen quite often. The electronic braking get over ridden because of the weight and it shuts down.

[Stephen Saar]

Well the good news is that it worked after unplugging it for awhile and plugging it back in :D . Ken, it might have been ov instead of ou, the display is a standard LCD 7 segment display so a v and a u would be identical I just assumed it was a u. Good call on the electrical storm. We had been having some lighting strikes and we lost power for a split second so that must have been what caused it. The lightning strikes were all far away so I didn't really think it was related.

Thanks everyone for the info. Very glad it just needed to be reset, I would have been a very unhappy person if I needed a new motor or controller box.

-Stephen

[Ken Fitzgerald]

Steve,

In researching 3 phase controllers, I vaguely remember some have an error code of "OV" which I suspect stands for OverVoltage. If you have lightning or storms in the area as line breakers are tripped you can have a lot of power fluctuations resulting in high voltage spikes that will cause an overvoltage condition.

[Bob Bergstrom]

Most owners of lathes with electronic variable speed controls either unplug them, or have a cut off switch to kill the power. If you have a lot of lightning in your area, it would be advisable to do one of these. I wouldn't think the warranty would cover electrical power surges.

[charlie knighton]

+1 keeping lathe unpluged unless using

[Tim Rinehart]

I had this exact thing happen Saturday, with some power flickering during storms coming thru. I opened the breaker and waited till LED went out, then closed breaker and all was fine.

As to removing power when not using the lathe...I used to do this every day, but somewhere I thought I heard (maybe even here somewhere) that cycling power to the VFD is on par with cycling a light bulb...the more often done, the greater the wear, so I've been leaving the lathe powered.

Anyone really know definitively if this is an issue with our lathes (cycling of power to VFDs).?

[Justin Stephen]

Would just connecting the lathe to a quality surge protector not accomplish the same thing?

[Scott Crumpton]

The 3520 us notorious for going blank once in a while. Unless you have had a power surge, just unplugging it for a minute will take care of it. It will reset itself. When I do big bowl it can happen quite often. The electronic braking get over ridden because of the weight and it shuts down.

A friend of mine picked up a used 3520a and was having constant problems with the OV error when turning the speed down to zero. It would even occur unloaded, with the pulley off the motor. We called Powermatic tech support. It turns out that some of the 3520a's didn't have breaking resistors. In some cases this would allow the back EMF from the motor to cause an over voltage condition on the controller's internal DC bus. The solution is to add the breaking resistor. If you're having this problem and your lathe doesn't have the resistor, call tech support and get one. It's less than $50. It made my friends lathe usable. The previous owner endured the problem for years.

And +1 for keeping it unplugged when not in use.

---Scott.