how would you run 220/3 phase to power an oddball 340v 3ph machine?
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  1. #1
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    Default how would you run 220/3 phase to power an oddball 340v 3ph machine?

    i looked around an only saw 120/220/440 . what about vfd's .. at different
    freq and voltage? i have plenty of current @220/3 , but am unsure how i
    would power a 340v (probably 50hz) weirdo- euro mill.

    maybe not so much the spindle as what is happening behind the scenes- power
    feeds , contactors, pumps, excedrin...

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    Cheapest way would probably be three 220-110 transformers wired as autotransformers (=330V) and connected to give the three phases.

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    How much HP?

    Three transformers would be pretty bulky and costly and probably give some phase imbalance.

    A VFD would do well, if you otherwise want a VFD on this service.

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    Quote Originally Posted by GregSY View Post
    How much HP?

    Three transformers would be pretty bulky and costly and probably give some phase imbalance.

    A VFD would do well, if you otherwise want a VFD on this service.



    A 440V VFD supplied by the same can easily be programmed to output the correct V/H curve to match that motor.

    As long as the curve intersects at the 330/50 point, added V at higher frequencies will work fine, and provide full power at over speed!

    Seems perfect to me, and just needs a 240/440 transformer and a VFD to match.

    (I happen to have both units that could be made redundant in my shop if interested ;-)

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    8kw @ rated . but that's subjective.

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    Three transformers will give no more phase imbalance than a three phase tranny. A 340 (should it be 380? that would be more common) Volt VFD will need a comensurate input voltage-> Back to square one! A three phase transformer would be more compact, but not neccessarily more economic or available.

    Don't worry about running a 50Hz machine on 60hz. yes, it will run 20% faster, but that won't hurt anything unless it's a clock.


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