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Powermatic 3520B VFD Replacement

Discussion in 'Tutorials and Tips' started by John Coppola, Apr 24, 2019.

  1. John Coppola

    John Coppola

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    Location (City & State):
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    About a week ago I had the VFD on my 3520B go out with a puff of smoke. I found two of the capacitors inside had blown. So I purchased and soldered on replacements but the failure also took out the controller board. In researching a replacement as I was not about to spend $600 on a 20 year old designed VFD I looked to see what I could do to replace it with something newer and more cost effective.

    After a bit of research, I landed on a Lapond SVD-P 3hp unit that I found on amazon for a little under $150 with a 5% off coupon. They do offer a different model that is 2hp that is only $100 and would do just fine but I would have been giving up the brake resistor which helps the lathe slow those big bowl blanks down quicker. There is also a 2hp version of the SVD-P but going over size means the VFD doesn't have to work as hard.

    Here is what I had to do to make the new VFD work with the Powermatic motor and controls.

    Here we can see what looks like a jumble of wires but it is not actually all that difficult to wire this up. I would recommend doing the larger cables on the bottom first as the smaller ones will get in the way. IMG_20190424_094103.jpg

    On the bottom left of the VFD we have the power in from the outlet which is 220V single phase. Being single phase the white and black can be switched without harm. Black and White go to L1 and L2. The greenwire goes to the ground on the left most terminal. You'll notice all of these have additional wires.The second Green wire on the ground comes from the motor. The Gray and Red wires are for the RPM readout. They, like the black and white wires does not matter which ones go where. You may have to strip away some of the covering from the main wire bundle to get the Red and Gray wires to connect down, while the rest of the bundle connects above to the other terminal blocks.
    IMG_20190424_094131.jpg
    Now looking at the lower right hand side of the VFD we have the brake resistor and motor connections. The brake resistor goes to the terminal towards the middle marked with the + and to the "PB" terminal, again these can be switched without harm. Now the remaining 3 wires from the motor do have an order to them as they are 3 phase 220V. Red goes to U, Black to V, and White to W.
    IMG_20190424_094120.jpg
    Now to connect the headstock controls we have to make a little modification to get everything to work right. The right most leg of the potentiometer is usually connected to the blue wire from the on/off switch. This will not work with this VFD. To get around the conflict we remove the white lead wire from potentiometer to the blue wire and instead connect it to a new wire that we add. I had a brown wire of about the same gauge so that is what I used. Route your wire through the head stock so that it won't get caught on any of the moving bits. You can wire tie it to the main bundle if you like. Make sure your blue wire is still connected securely to itself as it is still needed. IMG_20190424_094310.jpg
    Now onto hooking up the controls to the VFD. For the potentiometer we have the Yellow in the +10V terminal, Green in the AI1 terminal, and the new Brown wire to the GND terminal just below the+10V and AI1. The forward and reverse Black and White wires go to DI1 and DI2. The blue wire goes to the COM terminal. IMG_20190424_094115.jpg Now on to programming the VFD to our needs. This seems a bit intimidating but once you get the hang of the navigation it is pretty easy and explained pretty well in the manual which I do recommend on still skimming.

    First we want to input our motor information. For this we are going to select P1 and start setting P1-00 through P1-05 as follows.

    P1-00=1 (this is for the type of motor we have)
    P1-01=1.4 (this is the Kw of Power our motor can use. This could be set to 1.5 but I went on the low side)
    P1-02=220 (this is our motor voltage)
    P1-03=6.2 (the amperage of our motor)
    P1-04=50(we will need to change this later. You will see that you cannot set it higher yet. So just leave it for now)
    P1-05=3440 (this is our RPM of the motor which it does say 1720rpm on the motor plate but powermatic runs the motor a 120hz to get the speed up and is completely safe on its 4 pole motor)
    Now jump to P0 so we can change P0-10 and P0-12 both to 120. After changing P0-10 and P0-12 to 120 we can go back to P1-04 and change it's value to 120 as well. This will let us run the lathe at the intended top speed.

    Now we will run the autotune. Go to P1-37 change the value to 1 and press enter, then press the run button on the VFD. You will hear the motor make some odd noises and maybe turn a little but don't worry this is normal. Once it completes, the VFD display should say what ever HZ the potentiometer on the vfd is set to. We are ready to test the motor with the VFD controls. You can use the dial to change the speed of the motor and the Run and Stop buttons to start and stop. Your rpm should be showing on the headstock so just confirm that your max speed is what it was before. If you are not getting the right rpm at max check to see if you missed something from the settings.

    To use our headstock controls instead of the VFD's we need to change a few settings.
    P0-01=2
    P0-02=1
    P0-03=2
    P4-00=1 (if your forward/reverse switch is working in reverse swap this and P4-01 values)
    P4-01=2
    P4-02=0
    Now check to confirm your headstock controls are working as expected.

    Custom settings: Here are a few custom settings you may want to adjust to your liking.
    P0-17= Time in seconds that the lathe will take to speed up from 0-max RPM. If you want to go fast faster set this lower. Hope that last sentence made sense. I use 3.5
    P0-18= Time in seconds to decelerate from max RPM. Depending on the weight of what you are turning you may need to adjust this. If you frequently have the VFD trip and our work piece free wheels, (where it stops trying to stop the piece) you will want to increase this value. I use 4 for the time being but if big green blanks trip the vfd I'll increase accordingly.
    P8-12= The time the lathe pauses between forward and reverse when you flip the switch with the lathe running. The default is 0.0 seconds which I like to have at 0.2 so the change in direction is less likely to unscrew a chuck.
    P8-48= the VFD's fan control. 0= On only while powering the motor and 1= Always on. You may want to change it to always on to give yourself an audio cue to unplug the lathe or do like I did and wire a magnetic switch between the wall and the VFD so it isn't on all the time the way Powermatic had it from the factory. This is likely the cause of the somewhat early death of my VFD just outside of warranty.
     
    Rob Price and Clifton C like this.
  2. Clifton C

    Clifton C

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    Thanks for this write-up. I'm in the market for a VFD and motor combo for a, new to me, mini lathe so I'll add this info to the folder.
     
  3. Peter Woychesko

    Peter Woychesko

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    Thank you for this post. I very much appreciate it. My VFD on my 3520B has failed. I live in Canada so it will cost about $1000 Canadian if I buy it from Powermatic and have it shipped here. This post provides me with an alternative. I have found a Lapond SVD-PS on Amazon and will cost me $200.00 CND shipped to my house. Now I hope I can get it to work using your instructions.
     
  4. Mike Johnson

    Mike Johnson

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    This gentleman does a very good job in producing a series of videos showing a retrofit VFD installation on a standard lathe.
    He goes through the entire process showing motor replacement, controls, vfd, wiring and installations.


    View: https://www.youtube.com/watch?v=aGxA147fBqI
     
    Peter Woychesko likes this.
  5. Damon McLaughlin

    Damon McLaughlin

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    John, thank you for sharing your experience, the photos and outstanding instructions.
     
  6. Peter Woychesko

    Peter Woychesko

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    • Thank you, I will check it out.
     
  7. Doug Rasmussen

    Doug Rasmussen

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    John, that's an excellent write up on installing a new VFD. You made it very clear for VFD noobs.

    But, it almost sounds like the purchase decision was influenced to a some extent on low cost. Or, did you research the Lapond as being the highest quality unit available? (At one point I was under the impression Amazon tested and verified the quality of products they market, I no longer have that confidence though.)

    Based on reports of VFD failures on Powermatic machines it'd be fair to conclude they probably chose their VFD's based on price which appears to be back firing on them. Using VFD's with as short life as these does not speak well for Powermatic. Grizzly is about the same. Even Emiliano's fiasco with Stubby should be a lesson.

    A year ago I had the VFD nightmare of all time. 20 year old CNC machine tool with a dead Mitsubishi VFD. The Mit's unit was long ago obsolete , no keypad and required a separate plugin programming unit also obsolete. The inverter was highly integrated into the machine's control, must have been 15 to 20 wire connections to the Mit's. To make matters worse the terminal connections on the Mit's didn't correspond to current VFD standard nomenclature so it wasn't clear the function of some connections. Checking with a couple of the well known online VFD people it was obvious there were any number of 5hp VFD's at bargain prices that'd handle the needed capacity, but no in depth support. I settled on a Yaskawa which is the Rolls Royce of VFD's with a price to match, but factory support. It took a couple weeks for the Yaskawa people to research the old VFD and provide me with the connections plus parameter settings to the new unit.

    The point of my rambling on is in my opinion it's false economics to buy VFD's on price.
     
    Last edited: Sep 9, 2019
  8. john lucas

    john lucas AAW Forum Expert

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    If you look at the number of Powermatic machines out there vs the number of VFD's that have failed I think they must be holding up pretty well. After all most that have failed that we hear of are on machines that are over 10 years old. Wish we had good numbers on this but it seems like only in the last few years have we started hearing about VFD's failing. My friend who's machine is as old as mine (about 15 years now) had his fail but was pretty sure it was a lightening strike that killed it. Anyway I'm just saying that making a blanket statement that they chose inexpensive VFD and it's backfiring on them is probably not true. At least from my point of view.
     
    Ed Davidson likes this.
  9. Mike Johnson

    Mike Johnson

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    I was reading an article on VFD failures and the main cause was from several component manufacturers that were making poor quality capacitors that were failing in the field prematurely. When they rebuild VFDs these are the most common components that fail. Most manufacturers contract their control circuit boards and power supply boards to a sub-contractor, in turn these contractors go out to suppliers and manufacturers for their component needs which usually is determined by a bid process for these price sensitive components. One bad run of components can end up in a large number of electronic systems by multiple companies which had their components sourced through the poor quality source.
     
  10. Dean Center

    Dean Center

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    When my friend and fellow club member, and an electrical engineer, had to replace the VFD on his Powermatic, he researched and selected a unit that cost about $250. This was about $30 more than the cheapest available, but he thought it would be more reliable.

    Powermatic did use low priced Delta (not related to Delta woodworking tools) VFDs early on, and as John points out, they've held up pretty darn well. My friend's opinion is that currently available VFDs are much better than those used 15-20 years ago and it's not necessary to buy an expensive one in order to get a satisfatory product.
     
  11. john lucas

    john lucas AAW Forum Expert

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    One of the main reasons I purchased my Powermatic over the Nova DVR (I had previously owned 2 other Nova products and loved them) was that every part on the machine could be replaced by aftermarket pieces or rebuilt by a good machinist. I have had several friends need to replace the bearings, and one that I mentioned had the VFD die. Other than that the machines seem to be holding up really well. Oh I forgot, there have been several instances of breaking the spindle lock collar and many instances of set screws coming loose so interior parts move out of position causing clicking or other problems. The remote switch was the main issue. I simply replaced mine with something more substancial.
     
  12. Mike Johnson

    Mike Johnson

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    John, what kind of motor are they using on the Nova DVR? This is the machine that uses the headstock housing as the motor housing and the spindle is the end of the motor shaft? Is this an AC motor or a DC motor? When you read the specifications for the lathe they do not discuss these details.
     
  13. john lucas

    john lucas AAW Forum Expert

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    Not sure exactly what kind of motor they are using but its proprietary and if it died and company either didnt have parts or went out of business you would be screwed. I plan to have this lathe for a very.long time and that's why I chose the Powermatic.
     
  14. Bill Boehme

    Bill Boehme Administrator Staff Member

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    It's a stepper motor. The term variable reluctance describes how a stepper works and is mostly marketing buzz to make it sound special. John is right that you can't just buy an off-the-shelf drop-in replacement mainly because the motor housing appears to be an integral part of the headstock. Originally, steppers were used where you needed a small servo motor with highly accurate position and speed control. Typical examples were the motors in computer tape drives (in the olden days), hard disk drives, and DVD/CD players. They also were used in aerospace applications. Until about fifteen or twenty years ago steppers were small and not capable of delivering any power, but more powerful steppers became possible with the advent of high power switching semiconductors. Steppers are different. You can't just connect them to a power source. They have to be connected to a dedicated microcomputer that tells them what to do one tiny micro-step at a time. So the motor and electronics are dedicated to each other. Steppers are very reliable because their design is very simple, but complex microprocessor electronics are something to be concerned about. We have become acclimated to throwing away computers every few years, but I'm not ready to do that with a lathe.
     
    Roger Chandler likes this.
  15. Mark Jundanian

    Mark Jundanian

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    Not sure where this conversation morphed into the realtive merits of Nova DVR and Powermatic, and while acknowledging all the valuable comments above, I would mention that the DVR (stepper) motor has some nice features.
    It has 10 "radio button" presets for speed (and a knob) sort of like a blender.
    It always turns on to the #2 preset which I have set at 300, so it always starts slow.
    It can turn very very slowly, mine bottoms out at 50 RPM which is great for sanding.
    It can turn very fast, 3000. (I use a middle belt position).
    There is an electronic brake feature (don't use this with a Longworth unless you want the chuck to self eject-there's a reason I know this).
    On the negative side, the blister buttons suck, even after you stick on "bump stops".
    But it's about what matters to you most.
     
  16. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Mark, you mentioned belt position which leads me to think that I was mistaken about the design. I had somehow assumed that it was a direct drive. Maybe I have it confused with a different model.
     
  17. Mark Jundanian

    Mark Jundanian

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    You are both correct and incorrect. I should have clarified that I have the belt drive 1624 model with the DVR upgrade. The Saturn and Galaxy models are direct drive.
     
  18. Bill Boehme

    Bill Boehme Administrator Staff Member

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    After rereading the thread I decided that it deserves to be promoted to tutorial status so I am moving it to the Tutorials and Tips Forum and leaving a permanent redirect in the Woodturning Discussion Forum.
     
    Emiliano Achaval likes this.
  19. Emiliano Achaval

    Emiliano Achaval Administrator Staff Member

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    Excellent write up. Thank you for taking the time to do it.
     
  20. Don Wattenhofer

    Don Wattenhofer

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    I have a Grizzly that came with a stepper motor on it, the motor had a stick on label that said 220 volt 2 HP 3600 Rpm. The setup had very poor torque and the controller would trip out whenever I would try coring. The controller eventually fried so I fitted a 2 HP 3ph induction motor and a TECO VFD and the torque problems have disappeared.
     
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  21. RichColvin

    RichColvin

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    My MDF Rose Engine lathe now uses a stepper motor for the spindle drive. The value to ornamental turning is that I can now turn the spindle very slowly without losing torque. By slow, I mean REALLY SLOW : I can run at <1 RPM, though 10-15 RPM is more typical.

    It is a simple design using off-the-shelf stuff. A controller ($37), a drive ($39), a power supply ($27), and a display ($45), combined with a PCB board designed by Jon Magill and a few others. So, for around $175 + $29 for a stepper motor, I have a great spindle motor than has variable speed and no loss of torque at very low speeds.

    The very low cost of stepper motors and Arduino/Teensy controllers have made this something to be aware of. Combine those with low cost pillow blocks and linear bearings, & I think the turning community will see these more and more.

    Just look at the Nova DVR drill and all that automation. Who’d have thought that we needed anything more than a variable speed drive & a digital readout of the spindle speed? And some of us get along just finely with moving around belts.

    Imagine a push-button device that could do threading for you, or metal lathe capabilities like a feed screw synchronized to the spindle speed, or an automated version of the Flute Master or the Spiral Master. These are not outside the very near future’s realm.

    There is a market for these. Heck, look at what people will pay for a MADE lathe.

    This may not be for everyone (Gene Felder has a successful business carving bowls by hand!). But these technologies should be evaluated with an open mind before rejecting them. They may be really useful for your art.

    Just some thoughts.

    Rich
     
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