TEMCO phase converter installation - electrical assistance appreciated

John Hasler said:
Two pole 40 amp.
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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.
 
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.
 
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.
 
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.
Click to expand...

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.
Click to expand...

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.
 
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
100_0754.JPG


Input to the 1L1, 1L3 and ground
Output on the 2T1, 6T3 and ground (don't forget the jumper from 5L3 to 4T2)
100_0758.JPG

100_0754.JPG 100_0758.JPG
 
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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!
 
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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