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Thread: Powermatic 3520b inverter problem.

  1. #1

    Powermatic 3520b inverter problem.

    I have a 2003 Powermatic 3520b. I am very happy with the lathe except for a recent problem. I was turning a small bowl and I heard a pop-pop sound coming from the inverter. No power to the lathe. After calls to tech support, it was determined that I need a new inverter. $600. Yikes. I called an authorized technician and he estimated approx 2-3 hours to install. Not cheap but he has to make a living.
    After reading previous posts, I see that this is not a relatively rare event. Also, some folks have purchased inverters at other vendors with a much lower cost. However, the Powermatic folks discouraged this because a non-Powermatic inverter must be programmed.
    I am basically an idiot when it comes to electrical issues. Is this a job for the pros? Mainly, I want to get back up and running so that I can get back to turning asap. Thanks for your thoughts.

  2. Do a search for "Doc Green 3520b". And you should find a good amount of info, including inverter programming, electrical and he will allow you to converse over email, I think. There are threads about all issues related to 3520b lathes.
    Last edited by Roger Chandler; 08-10-2017 at 9:51 AM.
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  3. #3
    Join Date
    Feb 2008
    E TN, near Knoxville
    I was about to recommend reading Doc Green's web site too. He has some good debugging info.

    One thing you might check: I read that a dead Delta inverter on the PM is sometimes caused by a bad capacitor. There is a bank of capacitors accessible inside the inverter which should be easy to test and replace. If you are don't have much electronics experience you might get someone else to check it. I know there are companies and individuals who repair these inverters - the only name I have is this one that Doc Green gave me:
    One Stop Resource 3447 Denton Road Thomasville, NC 27360
    Phone: 877 - 434 - 6771 Website:

    I'm certain PM would discourage using another inverter! They want to sell you a new one. I found the inverter programming not a big issue once I studied it a bit and compared the parameters with the existing Delta inverter. (I do have electrical/electronics experience though.) I had a VFD on a Jet 1642 go bad and bought a less expensive 3rd party inverter (there are many available), probably $150 instead of $600. I programmed it with some suggestions from another turner, Harvey Meyer. I found my biggest fear was unfounded: the terminology of the parameters several inverters were all pretty close. I wrote down all the parameters for the jet then duplicated them as appropriate on the new inverter. I wrote the parameters in the Delta manual that came with the lathe (and the manual is available on line). If the display on your inverter will still power up you can page through the parameters and write them down. I think I may still have a file with the 3520b parameters or I get them from mine if you need it.

    Also, the last time I looked the exact Delta inverter the 3520b uses was available on eBay for much less than the Powermatic cost.


  4. #4
    Join Date
    Jan 2007
    Orange County, CA
    I have some electrical/electronic experience and replaced my inverter w/o any problems. The inverter wiring is well documented in the manual. I believe one wiring terminal was in a slightly different physical location on the new Delta inverter, but they are well labeled. It is a good practice to verify the wiring with the manual before removing the original inverter. As mentioned above, the programming password and parameters are available on line. The default parameters (there are a lot) are available from Delta and as I remember less than 15% are changed for PM.

    About 3 years ago, a replacement Delta inverter from an distributor was less than $300. It would require programming.


  5. #5
    I have replaced three or four inverters on friends Powermatic lathes. It is not a difficult job for someone with the right experience but is not a good choice for a 1st or 2nd electrical project. My favorite is the Hitachi inverters (about $300) for a 2hp inverter suitable for Powermatic lathe, they do have to be programmed. Less expensive inverters are available. Perhaps a friend could help. Replacing the inverter with the $600 unit from Powermatic would be easier but still requires several wires to be connected.
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  6. #6
    Thank you very much for the generous and helpful information. I will do some more research and will likely need a little help in the install. I will pass on some information that the Powermatic tech gave me regarding prevention. He said consider a whole house surge protector. Also, unplug the lathe when not in use.
    Thanks again and have a good weekend.

  7. #7
    Along the same lines, I would add to the advice to not turn on your lathe during electrical storms. I haven't had the unfortunate situation of damage to my lathe, but I do unplug it each time I am thru turning and I find something else to do when thunderstorms come thru.

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  8. #8
    One other tip. If you unplug it, wait 90 seconds berore you plig it back in. The inrush current before the capacitors are discharged, will sometimes blow your unit

    happy turning

  9. #9
    Join Date
    Jun 2016
    Beaufort, SC
    When I wired for my 220v Laguna lathe, I put in a single breaker box next to the lathe that feeds the receptacle. I shut down my lathe with the breaker.
    I am assuming a surge will not pass through an off breaker.The same circuit also feeds my 220v Bandsaw which is nearby. So when I'm finished, they are both "disconnected".
    Last edited by Joe Frank Porter; 08-12-2017 at 11:40 AM.

  10. #10
    Join Date
    Feb 2008
    E TN, near Knoxville
    Quote Originally Posted by John Keeton View Post
    Along the same lines, I would add to the advice to not turn on your lathe during electrical storms. I haven't had the unfortunate situation of damage to my lathe, but I do unplug it each time I am thru turning and I find something else to do when thunderstorms come thru.
    I have a double-throw 220v switch on my PM and turn it off every time I'm done for a while. The switch is in an electrical box stuck to the end of the lathe with magnets. I understand a strong power surge can still still come in through the ground connection, perhaps in the event of a close lightning strike. All my wiring is underground from the pole (about 1000 ft) and that is supposed to help.

    A failed inverter: I left my first Jet 1642 plugged in nearly all the time and after a few years it developed a flaky startup - if turned off I'd have to plug, unplug several times to trigger something in the electronics and allow it to work. Was the initial problem from a power surge? - who knows. After another 8-10 years of that the suddenly inverter died completely. I replaced it with a cheap one and it's been fine since.


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