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240 1phase to 575 3phase

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  • #16

    Re: 240 1phase to 575 3phase

    Re: 240 1phase to 575 3phase

    Hi, you can't run a three phase transformer from a single phase source and expect to get three phase power out.

    A single phase to 3 phase converter generates the other 2 phase relationships ( one 120 degrees advanced, one 120 degrees ****** from the single phase angle).

    This can be done with a rotary phase converter (good), or digital phase converter (rectifier/3 phase inverter) which is best.

    Static phase converters use capacitors to generate a phase displacement to start the 3 phase motor, however they are unbalanced and the motor runs at reduced power with increased heating effects.

    A VFD (Variable Frequency Drive) is a digital converter that takes incoming single phase AC and converts it direct current (DC). The DC is then fed to an inverter that produces 3 phase variable AC voltage and frequency to allow you to run a 3 phase motor from single phase power, and control the motor speed.

    Regards, Rod.
    Work is the curse of the riding class.

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    • #17

      Re: 240 1phase to 575 3phase

      Re: 240 1phase to 575 3phase

      I,d like to thank everyone who chipped in with some answers here, Think i,ve got a handle on it now. I haven,t sized anything yet fuses,wire,kva rating etc but does anyone see anything wrong with the layout in the attachment. Thanks Jim
      Attached Files

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      • #18

        Re: 240 1phase to 575 3phase

        Re: 240 1phase to 575 3phase

        I know this thread is from a couple of years ago Brian but if you can still dig up the name of the shop in Dorchester that sells used Electrical equipment including transformers I would be really interested @ this time. Weighing my options between a couple pieces of equipment single phase as well as three phase.
        Abe.
        Originally posted by Brian @ Muir View Post
        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

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        • #19

          Re: 240 1phase to 575 3phase

          Re: 240 1phase to 575 3phase

          Hi Abe, the one item mentioned is that you need an autotransformer to raise the voltage from 208 volts to 600 volts.

          You cannot use a conventional 600V delta primary/208V Wye secondary transformer and run it backwards. You will obtain the correct output voltage, however you will not have a ground reference on the secondary which is illegal, and dangerous.

          You need an auto transformer (common) or a 208V Delta/600V wye transformer (rare and expensive).

          Regards, Rod.
          Work is the curse of the riding class.

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          • #20

            Re: 240 1phase to 575 3phase

            Re: 240 1phase to 575 3phase

            Thanks Rod. I didn't actually state what my intentions were, I just copied and pasted this part "of the shop in Dorchester that sells used Electrical equipment including transformers" from Brian's post. I did a little digging and I believe he was referring to Relay Electric. I am looking at possibly putting 230 volt 3 phase using a rotary phase converter in my shop, I called Relay Electric but they don't deal with rotary phase converters.
            Abe.

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            • #21

              Re: 240 1phase to 575 3phase

              Re: 240 1phase to 575 3phase

              Abe.. It is Relay Electric. I have the same situation and my transformer cost me $275. Bought it used. It is hard to beat the cost of a rotary phase converter from American Rotary in Wisconsin. There is a recent post by Mark for the one he recently purchased from them.I am a big fan of Rotary Phase Converters.

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

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              • #22

                Re: 240 1phase to 575 3phase

                Re: 240 1phase to 575 3phase

                I have used phase converters since 1984.

                First, whether a 3 phase transformer is Delta or Wye wound ? A 4 wire winding will be Wye wound, that's 3 wires for the 3 phase one ( center of the Wye ) is the "neutral". All government installations require 4 wire systems. If your needs are for motor loads usual only 3 wire is required and Delta windings are fine. in 600 volt systems from any one of the legs to neutral should be 347 volts used for industrial florescent lighting.

                Static phase converters should be used only for single motor loads and cannot be used for a motor load that they were designed for. These are a phase shift circuit only and do not give full motor power.

                You can buy Vector drives that go directly from single phase to 3 phase and also have adjustable speed ramp up and down as well as variable frequency that gives you variable speed. Normal electrical motors are not designed for the higher speeds available and will overheat at lower frequencies.

                My choice is a rotary phase converter, they can be used for variable motor loads. I have a 45 hp unit that is supposed to only start a 15 hp motor, however starting smaller motors first actually helps the larger motors, if they aren't loaded. I can start a 25 hp saw spindle as long as I start the 10 hp and 7.5 hp motors first. To control the generated line voltage buy a unit with electronic voltage control, it switches extra capacitors in and out of the circuit when needed depending on the load.

                You do have to pay attention to the wiring, if you have manual starters the phase converter should be connected to restart by itself if the main should go off and back on, if you don't you could have 3 phase motors single phasing, not good. I only use magnetic starters.

                I have machines using 240 v 3 phase, 415 v 3 phase ( English voltage ) and 575 3 phase, and transformers dedicated for the last 2 the first coming directly from the phase converter.

                The start coil in your magnetic starters should not be powered by the generated phase and most converters will have an extra set of contacts for this.
                If you are looking for a quality Canadian manufacturer try Linda Munroe at T.J. Manufacturing 177 Samuel St. Sarnia ON N7T 7L3 519- 383-0433 or 866-230-4869 Linda is the most knowledgeable person I have talked to, she has manufactured phase converters for many years.

                I was trained as an electronic technician in the RCAF back in the late 1960’s I know that was a long time ago but electrons still do today what they did in the last century. Long before I decided to like working wood.
                Last edited by TH LWC; 07-06-2012, 01:28 AM. Reason: forgot something

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