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Jeff Steiner
07-02-2018, 1:51 PM
I received my 3520C, and am one of the lucky persons to not receive a power cable. The wiring diagram in the back of the manual is lackluster, and, to paraphrase the portion of the manual that talks about wiring the machine:::: "Don't screw it up. Have it worked on by an electrician.". I did some searching and couldn't find any direct help on the interwebs, so I decided that I would create a thread to help anyone else that was looking for help.

To set the stage, this machine requires 220V Single Phase power. This comes from grabbing 110V from 2 wires, and feeding them both into the machine.

I was in a situation where I had a breakout box with 4-wire 220V right next to where I wanted to put my lathe. There was no receptacle in the box, so I had the freedom to start with something new.

Ultimately, I purchased the following:
NEMA L620R receptacle (basically - a 3 prong plug that has a slight twist lock function). This plug is rated for 20 amps at 220V.
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NEMA L620P cord plug (matches the receptacle)

8' of 12-3 SJO cable (this is a flexible cable that has 3 insulated wires inside; a black, white and green).

Installation specific - I bought these as well
1" extension spacer for the 4" box (also called a 1900 box)
a plug plate for the 4" box

I started on the cable. This was pretty easy. The inside of the cable was labeled X, Y and G. Since both the White and Black wires of the 12-3 SJO cable will be "hot" (220v - 110v from each wire), it really doesn't matter. That said, Black is usually the X, and White (in this case - but Y is actually Red - more on that later) is hot, and will attach to Y. Green is ALWAYS ground - or at least you should always think of it that way. So - inside my plug from the 12-3 SJO cable:: Black to X, White to Y and Green to G.

Now to the other end of the cable - to the lathe. Inside the lathe power switch, there is some sharpie that says B-2, W-4..... Taking a look, you see that there are 2 other inputs on the switch itself.

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I first removed the rubber grommet inside the compression fitting that allows the cable to come into the box (the 12-3 wouldn't fit). I next removed the ground wire from the bar across the top, and just hard wired the Green wire to the "bus bar" - or "ground bar". Now, strip the ends of the White and Black and insert Black into the #1 hole, and White into the #3 hole. Tightly screw these in and push the cover back onto the box and screw it in.

Your lathe now has a power cable!

Next - onto the receptacle....

As I mentioned, my 220v box was run using 4 wires. Black, Red, White and a bare copper wire (Green). In this case, the White and the bare copper (Green) serve the same purpose. Your wires my be different - and if you're not sure, please talk to an electrician. Here's a pic of my shop panel.

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The 220V wire is fed through the bottom, to the breaker on the right side. You can see the Black and Red are wired into the breaker - these are the "hot" wires (or 110V each Black and Red == 220V). The White goes to a bus bar, as does the Ground.

To wire the receptacle, you simply need to wire up the Black, Red and bare copper to the plug. The white screws on a plug indicate electricity. Mine were labeled X, Y and G. I wired the plug up and put a wire nut on the "White" wire coming from the electrical panel. Basically the White wire is rolled up inside the box, and isn't connected to anything.

Screw it all in. Plug it in and try it out.

Worked for me.

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Of note - I have been told that all electronics come pre-filled with an appropriate amount of smoke built in. Under no circumstances do you want to release this smoke....... So - be careful. And know - just because you are excellent at woodworking, doesn't mean you have to be good at wiring stuff up. If you're not sure, do ask an expert.

Paul Williams
07-02-2018, 2:32 PM
Since you are using the white wire in your cable as one side of your 220V service you should mark it as such. ink, paint, red, or black electrician tape are all acceptable for marking. You don't want someone in the future looking at it and assuming that there is 110V between the white and black wires.

Jeff Steiner
07-02-2018, 2:44 PM
Since you are using the white wire in your cable as one side of your 220V service you should mark it as such. ink, paint, red, or black electrician tape are all acceptable for marking. You don't want someone in the future looking at it and assuming that there is 110V between the white and black wires.

That's a good point. The one thing to remember though is that the plug on the other end is a 220V plug, and won't go into a 110V outlet (assuming you're talking about the power cord for the lathe).

Damon McLaughlin
07-02-2018, 4:53 PM
I received my 3520C, and am one of the lucky persons to not receive a power cable.

It is my understanding that the 3520c doesn't ship with a power cord, at least I was told this by the Powermatic reps a couple weeks ago.

Thank you for your write up, very well written.

Jeff Steiner
07-02-2018, 5:54 PM
When I called PM support they said about 1/2 of them are shipping with cords. However, even if you received a power cord, it doesn't have a plug on it (and - it's not connected to the machine). Interestingly, the tech rep told me they were shipped with 8' of 14-3, which surprised me. I wouldn't think that 14-3 would be thick enough for the tool - but I'm not an electrician...

Brice Rogers
07-02-2018, 8:29 PM
Jeff, in general, 14 gauge is good for 15 amps. 12 gauge is good for 20 amps.

Alex Zeller
07-02-2018, 10:44 PM
Power cords are rated differently that the wiring in your house. The engineers who designed the lathe can base their choice of wire gauge based on is use. For example it's unlikely that the motor will be drawing the maximum current all the time the lathe is in use. They also can calculate what the allowable voltage drop would be for the lathe. The electrical code for wiring has no way of knowing what will be plugged into an outlet so they assume worse case.

Jeff Steiner
07-03-2018, 3:18 PM
I had no idea - thank you for the descriptive info. Makes much clearer sense now.

Power cords are rated differently that the wiring in your house. The engineers who designed the lathe can base their choice of wire gauge based on is use. For example it's unlikely that the motor will be drawing the maximum current all the time the lathe is in use. They also can calculate what the allowable voltage drop would be for the lathe. The electrical code for wiring has no way of knowing what will be plugged into an outlet so they assume worse case.

Jason Ramey
01-31-2019, 10:05 PM
Hello all. Just received 3520c and will beusing in a building with 208 3 phase power. Mine came with a cord but it wasn’t connected. It states in the manual that you must hardware the lathe. Is this correct?

Sam Beagle
02-01-2019, 5:54 PM
Yes. This is correct. But I would definitely check w PM to make sure you can use 208 3 phase. I guess you could make it work. But definitely check.

Joe Kaufman
02-01-2019, 7:19 PM
The manual clearly states 230V. single phase input. The local Rockler store manager mentioned last month that he had lost a few sales to schools and business that had 208V 3 phase distribution. He had talked to Powermatic and the response was 230V. single phase only. There was no plan to supply a version of the inverter that would take 3 phase also, similar to the 3520 A & B. I would be reluctant to hook up to a 2 pole breaker on the 208 distribution w/o prior approval from Powermatic or the inverter supplier. There may be more of a problem than the difference in voltage.

Jason Ramey
02-01-2019, 11:05 PM
Would a buck boost transformer take care of the issue? I found a 208 3 phase to 230 single rated to 20.8 for 200.00

Joe Kaufman
02-02-2019, 11:06 AM
I have the instruction sheet and parameter manual for the Delta VFD-S inverter used on the 3520B lathes. I do not know what inverter is used on the C model as it is covered. I quickly reviewed the S model inverter data and I see nothing that would cause me to question the 208V input. The voltage input tolerance is +-10% (180-264V). My concern is since the statement was 230V 1Phase only and over the years there have been various schemes to deliver the 208V 3 phase power. The relationship of inputs, say L1 and L2, with respect to a ground reference is different single phase 120-240 than 120-208 3 phase. I realize that a common is not connected and ground may not be used as an internal reference. In my past experience, the voltage difference mentioned was used to refute warranty claims.

Before you go the buck boost route and I doubt that it would correct the difference mentioned, I would try to get more info. Is your inverter a Delta Electronics unit? They have the manuals available in pdf form.

As a side note. there is a parameter for the B model inverters for 50Hz. input and another for 60Hz. I wonder if Powermatic has a part number for each?

Jason Ramey
02-02-2019, 3:23 PM
I have the instruction sheet and parameter manual for the Delta VFD-S inverter used on the 3520B lathes. I do not know what inverter is used on the C model as it is covered. I quickly reviewed the S model inverter data and I see nothing that would cause me to question the 208V input. The voltage input tolerance is +-10% (180-264V). My concern is since the statement was 230V 1Phase only and over the years there have been various schemes to deliver the 208V 3 phase power. The relationship of inputs, say L1 and L2, with respect to a ground reference is different single phase 120-240 than 120-208 3 phase. I realize that a common is not connected and ground may not be used as an internal reference. In my past experience, the voltage difference mentioned was used to refute warranty claims.

Before you go the buck boost route and I doubt that it would correct the difference mentioned, I would try to get more info. Is your inverter a Delta Electronics unit? They have the manuals available in pdf form.

As a side note. there is a parameter for the B model inverters for 50Hz. input and another for 60Hz. I wonder if Powermatic has a part number for each?
Hi Joe, wow, thanks for the great info! I will look at the inverter on Monday. It’s funny because the lathe is advertised as 220 v on all sites but the motor says 230v . If 208 works they would be great!

John K Jordan
02-02-2019, 8:19 PM
Hi Joe, wow, thanks for the great info! I will look at the inverter on Monday. It’s funny because the lathe is advertised as 220 v on all sites but the motor says 230v . If 208 works they would be great!

For some reason motors are listed at 115v and 230v. I checked the name plates on a bunch and they were all that way.

The US standard is actually 120v and 240v but in common usage many of us say 110v and 220v. Gets the voltage police upset!
This chart is from this document: https://www.pge.com/includes/docs/pdfs/mybusiness/.../voltage_tolerance.pdf

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JKJ

Sam Beagle
02-02-2019, 10:19 PM
I refinish wood floors for a living. And I use a buck booster for all my 208 jobs and I’ve monitored the voltage closely. Machine runs perfect.

Boyd Parks
02-19-2019, 1:26 PM
Just bought a new 3520C and it did have a cord, but no plug. I had already bought cord and a plug, so I didn't use it. I guess it was due to this thread I knew I needed it before I got the lathe. Thanks y'all!

David Walser
07-23-2020, 12:06 AM
The information in this thread was very helpful.

Reed Gray
07-23-2020, 11:05 AM
Not sure about all the electrical issues. However, it has been my experience at the convention centers, when turning on the lathes there, they seem underpowered, and it is supposedly due to the 208 or what ever volt 3 phase supply lines, which I think are aimed at commercial interests. Noticed this at several of the AAW shows, and at the Oregon Woodturning Symposium.

robo hippy