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3 Phase question

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  • 3 Phase question

    Can someone tell me which goes where----l1 s black l2 is red l3 is white----

    Phasematic IN power l1 is black--l2 is red ---- out the center would be white

    Just don't want to see any smoke today

  • #2
    Not totally understanding the question, but with 3 phase just connect each phase up. once all 3 are connected if it runs backwards just swap any 2.

    Just south of Sudspumpwater UK


    • #3
      I'm not sure I understood your question either. If you have a 3-phase power supply, any of the phases are identical, so it doesn't matter which way you connect them. As far as the direction of rotation, see Dave's post above.

      P.S. The only thing you should remember is if you use a rotary converter to create 3-phase, and your machinery has any single phase circuits, its better not to connect the circuits to the manufactured phase. It has nothing to do with the curcuit on the diagram though.
      Last edited by MichaelP; 12-21-2009, 02:13 PM.
      WI/IL border, USA


      • #4
        Not sure of your question BUT.
        Since you power is Black and Red on single phase input,
        you want the Black and Red on legs number 1 and 3
        as those are your fused legs.
        The white leg is your manufactured leg, and should be stated on convertor specs. Having a fuse on it will not protect you



        • #5
          I'm with Rich but I will add if the L1, L2, L3 are from the service panel as I assume they are then the red and black will come from the circuit breaker and the white will come from the white buss bar.

          BUT, what your saying is L3 is white and I have an issue with that. The red and black should be connected to L1 and L3 and white to L2. The reason is, as I understand the wiring of starter relays, the hot wires always go on the protected contacts where the heaters are shown, L1 and L3.

          Have you contacted the maker of your RPC?
          It's only ink and paper


          • #6
            Now..hold on here. I have a phaseamatic rotary. You need to get a handle on what you are doing here a bit... You will be feeding the rotary with 3 black and hot ground. The wires leaving the roatary will be black to to red...white to to green.

            You are correct that black and red run the converter and the white is the manufactured 3rd phase. BUT...when you go to connect to those wires the new colors for 3 phase will be brown, orange and blue for 277/480 or red black and blue for 240/3ph. Blue becomes the manufactured 3rd leg. You need to get a single phase switch to start the rotary...then feed the orange, brown and blue or for 240V black, red and blue wires to an appopriately sized 3 phase main breaker sized to protect the 3 phase system you will be installing. Think of it as having your own generation plant in the shop..feeding a main breaker ..then sub breakers for each of your machines. It really is a complete service system just like your single phase but you happen to have a generator that uses the grid to make the power.

            The switch for the rotary can be fairly cheap but you will find that a 3 phase main panel will be spendy. Oh and Square D breakers for the main and sub breaker are spendy too. You will want to keep to code with regard to colors and properly label the panels as to what they do ...and were the power comes from. Having multiple systems in one shop must be properly labeled should someone try to work on it they need a hint from labling and wire colors.




            • #7
              UH, UH, NO, NEVER use the green wire with the hot wires. The green is a MECHANICAL ground and is used to ground the housings and frames, etc. NOT on the hot side wiring.

              When you have two hot wires, red and black the return circuit is white, not green.

              By national code the service panel has two buss bars, one for white and one for green. The green is grounded to the panel and an earth ground but the white is floating, that is, not connected to any mechanical earth ground.

              If your using green for a neutral wire your in violation and could have problems with your wiring. Smarter people may change my mind but that is how I understand it.
              Last edited by Carld; 12-21-2009, 04:20 PM.
              It's only ink and paper


              • #8
                Originally posted by Carld
                By national code the service panel has two buss bars, one for white and one for green. The green is grounded to the panel and an earth ground but the white is floating, that is, not connected to any mechanical earth ground.

                Not so sure about that. Unless it's a sub panel (not all) the neutral and ground are bonded at the main panel.

                But yes... using the green wire as a neutral is plain bad... but... does code allow it to be reused if it's recolored - by say white tape? A ground would still be required in most cases.

                Many rotary phase converters are fed from "red, black, green" - neutral is not extended from the main panel and green is ground.
                Last edited by lakeside53; 12-21-2009, 05:07 PM.


                • #9
                  It's true that sub panels sometimes have the green and white together and maybe you can mark the green as white but it has issues. When I was building the home and shop I tried to look at the national elec code on line but you can't without paying. The only place I could see the code was at the library which I did and copied the pages that I needed. I have no desire to do that for this thread but others may do so or they may know the code.
                  Last edited by Carld; 12-21-2009, 05:17 PM.
                  It's only ink and paper


                  • #10
                    Maybe we're talking at cross purposes... it's the main panel that has the ground neutral bonding...

                    I'm too lazy to check my copy of the code (another computer blah blah ) but IIRC, sub-panels within the house typically have no bonding between neutral and ground, and sub-panels in other buildings will have a separate ground "rod" and branch neutrals will be bonded at that panel.

                    Jtiers will no doubt be along shortly to straighten this all out I'm off to search for the perfect xmas tree


                    • #11
                      All I can tell you is if the sub panel is located in an out building the white and green are bonded and the panel has a ground rod wired to the white/green buss bar. That is what was required in my area by the power company and local code. My service panel in the home and shop had to have isolated green and white buss bars.

                      It always struck me as odd because they are bonded outside of the house/shop panels in the meter base. Go figure.
                      It's only ink and paper


                      • #12

                        I never said or implied that the green wire was to be used as a neutral wire. Neutral wires are white. Green is mechanical ground or a bonding wire if you will. I simply mentioned the green to clarify that IF he has a green wire present then it would be hooked to green or the rotary chassis. The rotary uses two single phase hots to run it..there is no neutral needed as the rotary does not need to break any 115V from the pair. The rotary will have a red, black and white wire as well as a grounding screw. The black rotary wire will get a black wire from the grid and black wire TO the 3ph panel. The red will get a red supply wire from the grid and a red to the 3 ph panel. The white will act as the 3rd leg and will get a blue wire to the 3 ph panel. The green will connect to the rotary chassis..and to the chassis of the 3 ph panel. IF he wires it in conduit he can omit the green as the conduit will act as green.. IF there is flex conduit present then it is a good idea to run a green in the conduit as I don't trust flex to maintain continuity for grounding purposes.

                        For the is hooked to your lightning rod.

                        Red = hot
                        Black = hot
                        Blue = hot
                        Brown = hot
                        Orange = hot
                        Yellow = hot

                        WHITE = Neutral

                        GREEN = Ground

                        Bare Copper = Ground

                        Last edited by motorcyclemac; 12-21-2009, 09:58 PM.


                        • #13
                          Ok Mac, that I go with. It's much the same as I wired my home made RPC. The only reason I ran a white from the service panel is for the pony motor and a light to show the circuit breaker is on. He probably will need a neutral for the starter relay if it is 120v.
                          Last edited by Carld; 12-22-2009, 12:57 AM.
                          It's only ink and paper


                          • #14
                            Inspector had me mark the 230v line of my 3 phase red from the service drop to the fuse box. I am NOT very experianced with 3 phase! but the only trouble I have had to date is when I stupidly hooked up a single phase outlet power supply to the 220v wire! Hooking up anything else if there is a red wire I make sure the 230v wire connects to that.

                            Last edited by mark61; 12-22-2009, 09:55 AM.