Delta VFD inverter fan runs continuously when my PM3520A is plugged in.

[Charlie Goldberg]

This is my first post : ) I recently purchased a PM3520A from a member of my local turning club and finally was able to install the 220v circuit today. When I plugged it in, I was surprised to see that the fan on the inverter does not turn off (as far as I know). As soon as I plugged it in the fan started up and continued to run for about 15 minutes without me turning the lathe itself on... Is this normal? Is there a safe way to adjust the inverter so I can leave the lathe plugged in and the inverter fan will turn off after some time? It seems unnecessary that the fan would be running constantly if the machine is plugged in but not being used...

The lathe was built in 2004 and the guy who sold it to me said that the original inverter died around 10 years after he bought it. This seems common with what I'm hearing about others who bought the A model. He replaced the original VFD with a Delta model VFD015S21U about 5 or so years ago.

I'm cool to just plug and unplug when I'm not using it but it seems a bit silly to me to do this. Does anyone else have this experience?

 

[Kevin Jenness]

You can probably reset the fan function parameter but you will need the vfd manual. From what I have read here Powermatic does not support user programming of their inverters. Many people unplug or otherwise disconnect their electronic lathes when not in use to protect the vfd from power surges.

 

[Charlie Goldberg]

You can probably reset the fan function parameter but you will need the vfd manual. From what I have read here Powermatic does not support user programming of their inverters. Many people unplug or otherwise disconnect their electronic lathes when not in use to protect the vfd from power surges.

I'm wondering why they didn't include an on/off switch on the VFD in the first place. It makes me wonder if they did it because they actually don't want it to be turned off for some reason? I'm a bit boggled by it.

 

[Richard Coers]

Unplugging when you are done is a great idea for lightning protection. It takes very little surge to fry a VFD. I tried to find the release date of the 3520A. Wasn't it something like the year 2000? It doesn't surprise me that Powermatic didn't get everything perfect on a totally new design for them. What does your owner's manual say about unplugging the machine? You can also install a disconnect at the wall, the way that all industrial machines are installed so they have a safety lockout close by. That was probably the reasoning Powermatic did this. For all things Powermatic VFD, save this site; https://www.docgreenwoodturner.com/articles.html#Powermatic

 

[Mike Johnson]

You can easily install an inline disconnect switch for the outlet that powers your lathe receptacle. For worst case scenario you
want to break all of the wires going to the lathe receptacle. All bets are off if your house or service gets hit by lightning, in which case
you would be better off unplugging the lathe from the outlet entirely, that is the only way to guarantee the safety of the VFD. A high
enough voltage surge from a lightning strike can breach the gap on an insulated switch even when all the conductors are switched
open. If you switched the current carrying conductor only, you would still have the neutral and ground conductor that would conduct the
lightning strike into the VFD enclosure. At that point it gets really ugly.

 

[Dean Center]

The original Delta VFD on the 3520 did not have a fan. I'm no expert, but it seems common sensical to me that a fan and positive cooling implies a better quality VFD.

Since it's not the original VFD, there is no Powermatic induced prevention of fiddling with the parameters. One of the parameters should allow such protection, if the previous owner/programmer wanted to put it in.

 

[Mike Novak]

The c model has a power disconnect box on the back of the headstock mounted under the vfd. I’m sure you could buy these parts and retrofit. Might be cheaper to buy similar parts elsewhere

3520C-1103 ...............Main Switch
3520C-1105 ...............Main Switch box
JWL1440-141.............Strain Relief (2 required)

 

[Roger Wiegand]

Agree that you should be able to reprogram the VFD if you want to shut the fan off, but without a manual reprogramming an oddball VFD can get interesting. For a more convenient disconnect just install a "double pole" switch upstream of the outlet it's plugged into. Probably not quite as good for lightning as it leaves a continuous ground connection, but also more likely to get used regularly.

 

[Charlie Goldberg]

I'm gathering that it will be good practice to unplug the lathe when I leave the shop for the night or for a few days (and especially during storms) but it feels a bit clumsy to disconnect it from the wall every time I walk upstairs to eat lunch or go to another part of the shop for a couple hours. Running the fan continuously for multiple hours while the machine isn't in use just feels wrong to me. I think my best option is going to be to install and on/off switch for the outlet so I can at least power the inverter down while I'm not actively turning. And when I am stepping away from the shop for longer periods or during storms I will unplug from the wall. Thanks everyone, I really appreciate the help.

 

[robo hippy]

My Vic 240 will make a 'noise', which I think is a cooling fan on the motor for a minute or three after I hit the off switch. It does turn off eventually. Been a long time since I had the 3520A. Mine had a fan on the bottom of the phase converter and I had to put screen over the top of the baffles to keep the shavings out. I think a cooling fan works on most bigger self cooling motors, but not positive.

robo hippy

 

[Mike Drake]

The fan on the Allen Bradley drive I put on my P90 runs for a few minutes after I unplug the machine. ☺️

But, it normally cycles on and off as needed, though it can be programmed a variety of ways.

 

[Don Wattenhofer]

I'm cool to just plug and unplug when I'm not using it but it seems a bit silly to me to do this. Does anyone else have this experience?

I have 6 VFD's in my shop that I purchased and installed myself, none of them are Delta and some of them have fans and only 2 of them are regularly shut down. The other 4 are left connected all the time and have not failed, the oldest I installed on my Bridgeport milling machine when I got the mill in about 1998 is still going strong. Since I joined this forum there have been many instances of users seeking advice for failed VFD's and I believe they have all been Delta brand on Powermatic lathes and they also required a separate plug in unit to change or set any parameters, where as all of the VFD's I have can be programed from the front panel.
So what is the big deal about the fan running all the time!

 

[Don Wattenhofer]

The fan on the Allen Bradley drive I put on my P90 runs for a few minutes after I unplug the machine. ☺️

But, it normally cycles on and off as needed, though it can be programmed a variety of ways.

The fan will run off of the DC bus until that is depleted.
I have a P90 that I installed a Teco VFD on and the VFD appeared to fail but it turned out that there is a thermal overload relay connected to the motor that had tripped due to hard use.

 

[Brent Sobotka]

If you have the ability to reprogram the Delta (E) VFD. Group 03, Parameter 08, 0 = Fan always on, 1 = 1 minute after AC motor drive stops, fan will be OFF, 2 = Fan ON when AC motor drive runs, fan OFF when AC motor drive stops, 3 = Fan ON when preliminary heatsink temperature attained (ON: 60℃, Off: 40℃)

I believe that 3 is where Powermatic programs the VFD. I don't see any option to turn it off altogether.