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  • 240 1phase to 575 3phase

    So i,ve got three older machines all 575 and only 120/240 in the shop my question is can i feed a step down transformer backwards to give me the voltage i need. For testing purposes could i feed x1 and x2 from the panel and get 600 across h1 h2 h3 and have it run the motors. Also if this would work would the neutral on the secondary have to be used. The shop has 100amps i,ve got a 7.5kva transformer and the largest motor only draws 5.5 amps so i think i,m covered that way. Any ideas would be abbreciated. Thanks Jim

  • #2

    Re: 240 1phase to 575 3phase

    Re: 240 1phase to 575 3phase

    So how are you generating your third phase as a delta to the other two phases, VFD or Rotory or Static? That will help answer the question.
    Cheers, Mark
    sigpicToday's mighty oak is just yesterday's nut, that held its ground.

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    • #3

      Re: 240 1phase to 575 3phase

      Re: 240 1phase to 575 3phase

      Hi mark Thats what i,m asking will the transformer give me all three phases or only two phases at 575,if that makes any sense.
      Last edited by Groovin Rubin; 09-15-2010, 08:28 PM.

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      • #4

        Re: 240 1phase to 575 3phase

        Re: 240 1phase to 575 3phase

        Maybe i,m asking the wrong question would feeding 240 volts into the secondary side of the transformer give me a usable voltage on the primary side. I,m thinking of a vfd on a large bandsaw but don,t want to buy vfd,s for everything that might come thru the shop. From what i,ve read a RPC would work if my motors were 220/440.3ph but not straight 575. Maybe i,ve missed something. Thanks Jim

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        • #5

          Re: 240 1phase to 575 3phase

          Re: 240 1phase to 575 3phase

          No. The transformer can only change the voltage up or down, it cannot itself make three phase power out of single phase. As Mark implied in his question some other device (a VFD, or static or rotary phase converter) is required to generate the missing phases. Also be sure you talk to someone who knows what they are doing here, 575 Volts is not for casual experimentation.

          Ian

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          • #6

            Re: 240 1phase to 575 3phase

            Re: 240 1phase to 575 3phase

            Originally posted by Groovin Rubin View Post
            Hi mark Thats what i,m asking will the transformer give me all three phases or only two phases at 575,if that makes any sense.
            If I understand you correctly, You just have a transformer at this point. It will bost the voltage to 575 but you still need a phase converter of some sort to generate the third phase and put them into alignment of the three phases. Think of power moving between two points on single phase going back and forth, then in three phase you have a triangle (delta), three hot with the electricity running around, thats why you don't need a start winding in three phase.
            Bottom line the motor won't run otherwise. (Wiki phase converters if you need more info.) You tend to feed the phase converter with your 2 hots of 220V, generate the third phase with the phase converter, then boost it up using the transformer to down to 208 or up to 308V, 440V, 575/600V ect to what your machines need or directly from the phase converter to the machine in the case of 220V three phase.
            Brian in Muir, offered to show you his rotory phase converter, I am farther away, it is basicly a rewound motor working as a generator, this is what you need! Look up rotory phase converter companies on the internet like American Rotory. Because you have a few machines a VFD is going to get expensive at one per machine. A static phase converter is touchy and can be problems and often week on the third phase. There is a new type called phase perfect, an electronicly generated unit now being made but very $$$$.
            I hope this helps, I am not an electrican so most of what I know is from my Dad.
            Cheers, Mark
            Last edited by Mark in Burlington; 09-15-2010, 09:52 PM.
            sigpicToday's mighty oak is just yesterday's nut, that held its ground.

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            • #7

              Re: 240 1phase to 575 3phase

              Re: 240 1phase to 575 3phase

              Originally posted by Groovin Rubin View Post
              Maybe i,m asking the wrong question would feeding 240 volts into the secondary side of the transformer give me a usable voltage on the primary side. I,m thinking of a vfd on a large bandsaw but don,t want to buy vfd,s for everything that might come thru the shop. From what i,ve read a RPC would work if my motors were 220/440.3ph but not straight 575. Maybe i,ve missed something. Thanks Jim

              This may answer a few questions. Then ask again.

              http://www.3phasepower.org/rotaryphaseconverters.htm

              http://www.google.ca/#hl=en&source=h...82fea2a28ce27c

              Hope that helps
              Last edited by willr; 09-15-2010, 09:29 PM.
              ---
              Will

              “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” —- Mark Twain

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              • #8

                Re: 240 1phase to 575 3phase

                Re: 240 1phase to 575 3phase

                my friend has a bunch of 550 metal working machines
                people are correct
                you need a rotary phase convertor to give you 3 phase 220 then to the step up transformer to give you 550 on the power supply to equipment side


                for what youre trying to do don't think i would go the vfd or static route

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                • #9

                  Re: 240 1phase to 575 3phase

                  Re: 240 1phase to 575 3phase

                  I have a 575 transformer in my shop to run my Dust Collector. The rest of the machines are 220 as they came from the US where 220 and 440 are the most popular voltages. I should be back in the shop next week if you want to drop by.

                  Brian
                  If your dreams don't scare you, you are not dreaming big enough

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                  • #10

                    Re: 240 1phase to 575 3phase

                    Re: 240 1phase to 575 3phase

                    Guys i was hoping not to have to bring this up but i,m an electrician (33 years) it,s just i,ve never ran into this one before. Also just to save a little face here i asked an electrical engineer that works at one of the nuclear plants here in ont how i could go about this. His reply was he,d get back to me on that (that was a week ago) o well. I,ve searched the net every nite for the last two weeks regarding this and always came up with the 220/440 solution,not 575.If i had a schematic i can make it work.Brian i read on OWWM that before RPC guys would use transformers to do the same thing is this what your doing with your DC.I,d love to have a look at your set up only problem is i work away from home most weeks so it may be awhile before i can get there. Sitting in a motel room typing this as a matter of fact, same darn room for the last 14 months would of gone crazy long ago if not for this site and a few others.Thanks for your replys guys i,m alot closer to figuring this out Take Care Jim

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                    • #11

                      Re: 240 1phase to 575 3phase

                      Re: 240 1phase to 575 3phase

                      Jim... My first hurdle to overcome was convincing my friend who is a fully licensed Industrial Electrician and probably about your experience. First he tells me that phase converters don't work and if it does work the voltage on the 3 rd leg will be lower than the other two. He then opened the box containing the capacitors and other electrical components. Immediately informed me that the wiring was not heavy enough guage. At this point I suggested we should phone American Rotary and he could speak with them. After speaking with American rotary he said he was not convinced and wanted to take it to his Boss and get his opinion and he was not sure that American Rotary knew what they were talking about. They did supply several options for wiring but he was not interested in them

                      After several weeks of phone calls he finally got it up and running with the coaching from American Rotary. It has been running ever since and that has been approx 5 years. American Rotary use a 3 phase generator that is rated as the Same HP as your phase converter. I am sure a 20 hp 3 phase motor would soon eat up $500.

                      last year I bought another 20 hp unit to run in tandem with the first, used a different electrician and it was no problem. The licensed electrician knew that they worked and one call to American Rotary and we were up and running. One little glitch we ran into is that when running multiple machines the phases all have to be balanced as initially all I got on the wide belt was some thrashing noises. Took him a few minutes to figure that out.

                      If I get a chance I will take some photo,s of my panel and set up. They both run from a 100 amp single phase panel. My first RPC was wired to a junction box. From this junction box one line went to the transformer that jumped it up to 575 volts and on to the DC. Another line went directly to the slider. As Mark suggested, take a look at the American Rotary site.

                      Brian
                      If your dreams don't scare you, you are not dreaming big enough

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                      • #12

                        Re: 240 1phase to 575 3phase

                        Re: 240 1phase to 575 3phase

                        I just might be missing something here........?????...........can't say for now,but wouldn't it be simpler & more economical to just replace your 3ph motors with some used 1ph ones?especially if they're not big motors?

                        andre

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                        • #13

                          Re: 240 1phase to 575 3phase

                          Re: 240 1phase to 575 3phase

                          There is a fair number of guys on Sawmill Creek and Woodweb that run phase converters. I am not sure if you are aware of the shop in Dorchester that sells used Electrical equipment including transformers. About half the price of new. The name escapes me at this time but I can dig up the name if you are interested.

                          brian
                          If your dreams don't scare you, you are not dreaming big enough

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                          • #14

                            Re: 240 1phase to 575 3phase

                            Re: 240 1phase to 575 3phase

                            Originally posted by Andre in Quebec View Post
                            I just might be missing something here........?????...........can't say for now,but wouldn't it be simpler & more economical to just replace your 3ph motors with some used 1ph ones?especially if they're not big motors?

                            andre
                            One big advantage to 3 phase is that used equipment is probably 1/2 the cost of single phase. I sold a 3 hp Powermatic shaper for $150. Probably get $500 easily if it was single phase but you are correct in assuming for a 3 hp motor it would be easier to change the motor as long as the motor would fit without requiring a machine shop to make brackets etc. and you did not have several machines to switch over.

                            Brian
                            If your dreams don't scare you, you are not dreaming big enough

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                            • #15

                              Re: 240 1phase to 575 3phase

                              Re: 240 1phase to 575 3phase

                              Originally posted by Brian @ Muir View Post
                              One big advantage to 3 phase is that used equipment is probably 1/2 the cost of single phase. machines to switch over.
                              Brian
                              Just to pick up from Brian, It is nice to go to an auction and be able to buy anything providing your phase converter is big enough and you transform to the right voltage.
                              You can't always do the motor switch over, I have a bandsaw that has a motor 6 pole direct drive three phase. These motors are smaller than the same equivelent size single phase when you don't need start windings and a capacitor, so they don't always fit, it adds up doing a motor change over, motor+magnetic switch and rewire also a single phase 5 hp and larger is also really expensive. The tipping point is about 2-3 machines for cost, I have 6 running off my converter. Also many tools now have special mounting, Euro motor can be unique sizes or if they have other electrical parts for breaking or locking out ect. Once you made the leap many machines are available for a fraction of the cost of single phase in the used department.
                              Cheers, Mark
                              sigpicToday's mighty oak is just yesterday's nut, that held its ground.

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