Ideas for running 3 phase CNC machine on single phase.
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  1. #1
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    Default Ideas for running 3 phase CNC machine on single phase.

    I have moved to a new workshop which unfortunately doesn’t have a 3 phase power supply. So I am stuck with 240v single phase at the moment.
    I have a 3 phase planer thicknesser, Mortiser and dust extractor which I’m not too concerned about as they all run from a 5hp static phase convertor that I have.

    But I am having problems finding a solution for the CNC machine.
    I am waiting for a price to put in a 3 phase supply, but I’m expecting it to be prohibitively expensive.

    The spindle fitted is 4.5kw 380v 400hz 24,000rpm. (Can this be fun on 240v 3 phase with reduced torque?)
    The VFD fitted is 380-480v 3 phase input, 0-380v 3 phase output. 5.5kw (can this run from a phase convertor?)

    The options I can think of at the moment are:
    Get proper 3 phase installed
    Build a rotary convertor (maybe using my static and a large motor?)
    Replace the vfd with a 240v in 380v out (I’ve seen one of these but it seems too cheap!)
    Replace the vfd with 240 in 240 out and run the spindle on 240v
    Replace both vfd and spindle.

    Does anyone have any suggestions or pointers?

    Thanks for taking the time to read!
    Mark.

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    What fuses has your 240 volts ? Need 20 amps minimum for 4.5kw
    And is your motor dual voltage 400-240 volts ??
    If so I would swap the VFD with a 240volts single phase unit


    Peter

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    Thanks Peter.
    20amps shouldn’t be a problem.
    The spindle only says 380v, but I think I read elsewhere on this site that it will run on 240v but with reduced torque at higher speed.
    This is the same spindle:
    302 Moved

    Thanks Mark

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    Can anyone confirm if the VFD would run from a Rotary Phase Convertor?

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    Most 3 phase VFD's will run off of a RPC, there may be some small derating if driving difficult loads.What you might look into is a Phase Perfect digital phase converter, they have newer models that have voltage doublers and run off of single phase. You could give them a call to see if the output voltage is adjustable. Alternative would be some combination of a RPC and step up transformer. The Phase Perfects are pricey, but probably more cost effective then pulling in 3 phase power, it all depends on the numbers.

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    I came across this: YouTube

    Thinking that it was interesting, but of not much use to me. It might be useful to you though.

    From the video:

    "DIY rotary phase converter producing 415 volts 3 phase, from a 240 volt single phase supply.
    This converter overcomes a number of issues with old and difficult to run motors, that other converters struggle with."


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