# TEMCO phase converter installation - electrical assistance appreciated



## ecdez (May 25, 2014)

I picked up a TEMCO phase converter a few months ago and am finally getting around to installing it.

Here's the first issue I noticed and thus my first question.

If you look at page 5 in the instruction manual (http://attachments.temcoindustrialpower.com/Data_sheet/XR11_Data_Sheet.pdf) it shows that the single phase side is grounded but the 3 phase side is not.  I've read a few things that say that 3 phase is not required to be grounded.  OK, fine.  I look at my machines though and they have plugs with 4 prongs.  What's a guy to do?


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## hermetic (May 25, 2014)

You should bond together the incoming ground, the ground on the Temco unit, and the machine ground connections to form a common ground point.


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## ecdez (May 25, 2014)

I was thinking it had to be grounded, it just didn't make sense to me for it not to be.  That said, I'm a experienced novice with electrical wiring and a total virgin at 3-phase.

Thanks for the response.


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## John Hasler (May 25, 2014)

ecdez said:


> I picked up a TEMCO phase converter a few months ago and am finally getting around to installing it.
> 
> Here's the first issue I noticed and thus my first question.
> 
> If you look at page 5 in the instruction manual (http://attachments.temcoindustrialpower.com/Data_sheet/XR11_Data_Sheet.pdf) it shows that the single phase side is grounded but the 3 phase side is not.  I've read a few things that say that 3 phase is not required to be grounded.  OK, fine.  I look at my machines though and they have plugs with 4 prongs.  What's a guy to do?



They mean that none of the three phase conductors (T1, T2, T3) are normally grounded.  The fourth prong on your plugs is for the non-current-carrying "green wire" safety ground that connects to the frames of the machines.

The ground symbols in that drawing represent the safety ground for the non-current-carrying metal parts of the system.  They do not connect to any current-carrying conductors.


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## ecdez (May 25, 2014)

So from the receptacle to the converter I should be using wire like below, 3 hots and one ground.

 I believe the tag on the RPC says 4g min for incoming power (box to RPC) and 8g min for OUTGOING (RPC to machine)


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## John Hasler (May 25, 2014)

ecdez said:


> So from the receptacle to the converter I should be using wire like below, 3 hots and one ground.
> 
> I believe the tag on the RPC says 4g min for incoming power (box to RPC) and 8g min for OUTGOING (RPC to machine)
> 
> View attachment 77529



Color all exposed portions of the white wire black with a Magic Marker so that it will not be mistaken for a neutral in the future.  Also clearly mark the receptacle "THREE PHASE".


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## Wireaddict (May 26, 2014)

I use a Temco RPC also for a lathe in my shop.  I'm glad you enclosed a link showing the wiring to the RPC; the drawing actually shows the safety disconnect switch housing grounded as Mr. Hasler indicated.  It never hurts to ask!


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## ecdez (May 27, 2014)

I hear they're good unit.  Are you pleased with yours?


I saw the safety switch was grounded but my confusion lied at the other end, where the machine would be.  The drawing doesn't show a ground coming from there.  Maybe because they don't show a machine, just another switch.




So I'm digging into this further and have come up with another question.  Hopefully this will help someone else in the future who may have a similar issue.  The motor has this label on it.




If you zoom in you can see that it says under input "min wire 4 agw"
It also says under output "min wire 8 agw"


When I look in the manual that I linked in the original post on page 3 it says;
"recommended 1-Phase (input) wire size - 8 agw"
"recommended 3-Phase (output) wire size - based on load requirement"

That's a big discrepency on the input side between 4awg and 8 awg.  Any ideas why?  I called and asked a question today about something else and the response was less than helpful.


So I did a little math based on the guidelines in the manual.  The largest machine I have is rated at 13.7 amps @ 220 volts.  13.7 * 1.732 (from the manual) gives me 23.73 amps on the single phase side.  There's a built in overload of 32 amps also.  From what I've read, 8g should be good to 40 amps.  Am I wrong in this?


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## John Hasler (May 27, 2014)

ecdez said:


> I hear they're good unit.  Are you pleased with yours?
> 
> 
> I saw the safety switch was grounded but my confusion lied at the other end, where the machine would be.  The drawing doesn't show a ground coming from there.  Maybe because they don't show a machine, just another switch.
> ...



You would need 4G if you were going to run the thing at its full load rating of 66A, but you aren't.  The wire size on the input side should be adequate for the rating of the circuit breaker it is fed from.  If you feed it from a 40A breaker 8G will be ok.


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## ecdez (May 27, 2014)

John Hasler said:


> You would need 4G if you were going to run the thing at its full load rating of 66A, but you aren't.  The wire size on the input side should be adequate for the rating of the circuit breaker it is fed from.  If you feed it from a 40A breaker 8G will be ok.




Thanks for all your input.  I'd still be scratching my head.

Since it's 220v in would it be a dual 40 breaker or a dual 20?


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## John Hasler (May 27, 2014)

ecdez said:


> Thanks for all your input.  I'd still be scratching my head.
> 
> Since it's 220v in would it be a dual 40 breaker or a dual 20?



Two pole 40 amp.


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## ecdez (May 27, 2014)

John Hasler said:


> Two pole 40 amp.



Thanks John.

I think I'm gonna chronicle my exploits from the box to at least one machine.  I havn't seen that on the web yet and I hope it will be helpful to someone in the future.  I certainly don't expect you to be my personal adviser but if you could point out any obvious errors that might kill me I would appreciate it.


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## jim18655 (May 27, 2014)

You might want to consider connecting it for the full load it's capable of running. It will cost less to do it once then to re-do it later when you add machines.


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## Wireaddict (May 28, 2014)

ecdez, you asked me if I was happy with my Temco RPC, yes, I never had any trouble with it.  As of now I only have one 3-phase machine, a Sheldon lathe but, unfortunately I discovered _after_ I bought it that the motor was ONLY 480V [3-ph], not 240/480V like most motors this size so I also had to buy a step-up tranny for it.  If I had known this I wouldn't have bought that lathe.  I paid $1500  for it & around $1800 for the RPC, 6 KVA transformer, safety disconnect switch, fuses, starter, wire, conduit, etc., & most of the equipment was used except for the RPC otherwise it would've been a lot more!  Fortunately there was no labor since I wired it all myself.  Another plus was that the lathe came with a stand & 2 drawers full of goodies.

 I noticed that item D on the schematic wasn't grounded; I think this was an oversight because everything metal needs to be grounded including the machines.  A few comments: although the schematic specifies a magnetic starter at location D I wired the RPC output directly to the 240V winding of the tranny & installed a [600V, 30A, fused] safety disconnect after the transformer on the wall next to it [plus the lathe came with an unfused safety disconnect already installed [important since it's about 12 ft from the fused disconnect on the wall by the RPC].  Also, although the RPC can handle about 72 amps in I need less than 10 amps out [240V, 3-ph] so I fed mine from a 2-pole, 40A breaker, #8 wire, a NEMA size 2 motor starter [item A] with overload heaters rated for about 30A to handle the starting inrush current.  I also used #10 wire between the 3-ph RPC output & the transformer although 12 or even 14 gage wire would work.  For the 480V, 3-ph wiring to the lathe I ran #12 wire through 1/2 inch thin wall conduit [also called EMT].  Finally, I put 3-5A fuses in the 480V safety disconnect by the tranny & RPC.


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## ecdez (May 28, 2014)

jim18655 said:


> You might want to consider connecting it for the full load it's capable of running. It will cost less to do it once then to re-do it later when you add machines.



I had considered that and your right, it would be cheaper.  Problem is I have no room for any more tools.  I also need to get up and running right away so my budget and will probably push me to going smaller and regretting it later.

- - - Updated - - -



Wireaddict said:


> I noticed that item D on the schematic wasn't grounded; I think this was an oversight because everything metal needs to be grounded including the machines.  A few comments: although the schematic specifies a magnetic starter at location D I wired the RPC output directly to the 240V winding of the tranny & installed a [600V, 30A, fused] safety disconnect after the transformer on the wall next to it [plus the lathe came with an unfused safety disconnect already installed [important since it's about 12 ft from the fused disconnect on the wall by the RPC].  Also, although the RPC can handle about 72 amps in I need less than 10 amps out [240V, 3-ph] so I fed mine from a 2-pole, 40A breaker, #8 wire, a NEMA size 2 motor starter [item A] with overload heaters rated for about 30A to handle the starting inrush current.  I also used #10 wire between the 3-ph RPC output & the transformer although 12 or even 14 gage wire would work.  For the 480V, 3-ph wiring to the lathe I ran #12 wire through 1/2 inch thin wall conduit [also called EMT].  Finally, I put 3-5A fuses in the 480V safety disconnect by the tranny & RPC.



Thanks for the details!

My first 3-phase machine was going to get a VFD but then another 3-phase machine was given to me.  Once I decided to go with a RPC I ended up getting 3 more 3 phase machines so now I have 5 total.  All are smaller than the one mentioned above.

I can't even use half the stuff in my shop until I get this thing going so it's gonna get prioritized on my to do list.


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## ecdez (Jun 2, 2014)

I actually made some progress.  Got the panel wired to the magnetic starter and the starter wired to the RPC.  I picked up some wire this morning so later this week I should have some machines humming.

Anyway, on to the pictures.


One note, the schematic inside the magnetic starter showed which terminals the motor hooked to but not the power coming in.  Long story short, I had it wrong and had to call WEG's tech support line; 6pm on a Sunday night and someone answered!  Apparently those guys are on 24hr call.  This guy was at home and walked me through my problem.  After a 10 minute call he told me he didn't have anything in front of him because he had it all memorized.  Thought guys like that were extinct.

40 amp, 2 pole breaker w/ 8-2 cable




Input to the 1L1, 1L3 and ground
Output on the 2T1, 6T3 and ground (don't forget the jumper from 5L3 to 4T2)


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## Wireaddict (Jun 3, 2014)

Glad you got it working.  One thing I liked was the location of your 2-pole, 40A breaker in your power distribution panel; any circuit that draws a lot of current like the RPC's starting current, electric heaters, welders, compressors, etc., should be close to the main breaker or, in your case, the main lugs to minimize voltage drop over the length of the bus bars & possible heating.  One minor point, though, I'd get some black [or maybe red] electrical tape or a felt tip marker & identify the white white wire that runs between the 40A breaker to the starter as a hot wire so it's not confused with a neutral.  Regards!


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## ecdez (Jun 3, 2014)

I thought of coloring the white wire as black after I took the picture.  Someone mentioned it earlier above as well.


The breaker position happened by accident.  I thought I bought a foot of extra wire but turns out is was about 6" short.  To compensate, I dropped all the other breakers on that side down two positions so this one would reach the wire.  I accidentally did it right.


Thanks for the input from all.  This had been in the corner of the garage since January because I was scared of hooking it up for some reason.  Like most things, once I got started it was not a big deal.


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## ecdez (Jun 20, 2014)

Got the electrical hooked up at the RPC.  Hooked up a machine just to check it out and it appears everything works.  Need to run the cables through the wall and hook up permanently but I'm pleased so far.

Took a video of it running.  It's quieter than I thought it would be.

https://www.youtube.com/watch?v=5P_9KjCTESQ&feature=youtu.be


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