Single phase or 3 phase

This topic contains 8 replies, has 2 voices, and was last updated by  Barton Gilliam 9 months, 3 weeks ago.

  • Author
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  • #8291

    Barton Gilliam
    Participant

    For small horse power applications single phase is okey
    for high power applications , suppling single phase to driver will couse un balanced load to the utility side, and you will need larger filters to smoth the dc side of the circuit, right?


  • #8292
    John C
    John C
    Galco Representative

    Well Barton your not wrong. Truth be told is most VFD mfg’s won’t build a drive for single phase operation above 5HP anyway. You might find the odd 10HP drive that will accept single phase but above that they usually require 3 phase power. Now if single phase power is all you have available, you can get what is called a “Phase Converter” that will generate 3 phase power from your single phase supply.
    Hope this helps


  • #8293

    Barton Gilliam
    Participant

    Ahh ok then, so what horse power do Phase converters go up to?


  • #8294
    John C
    John C
    Galco Representative

    Ok Barton had to do a little research for this 1. A company called “Phase-A-Matic” builds up to 100HP rotary phase converters. However, if you are line starting a motor directly off of the converter, these guys will only do up to a 50HP motor and provide full starting torque. Reason being that AC induction motors line started will pull 5 times their rated current.
    Cool?


  • #8295

    Barton Gilliam
    Participant

    Ok well how do I get the full 100HP motor to start on it?


  • #8296
    John C
    John C
    Galco Representative

    You would have to use a “Soft Starter” on it, assuming you don’t want variable speed.


  • #8297

    Barton Gilliam
    Participant

    What if I do want variable speed?


  • #8298
    John C
    John C
    Galco Representative

    Then just use a VFD instead. It will provide low current starting up to 100% speed of the motor you have configured on it. OK?


  • #8299

    Barton Gilliam
    Participant

    Ok John thanks for all your help


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