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  1. #1
    Join Date
    Apr 2014
    Posts
    11

    How Many Amps Needed

    How do you figure how much power a machine needs? will it always run at the same amp draw?
    I am retrofitting a MultiCam 1000 4'x8'.
    It has a 5hp spindle.
    2 6amp motors on X
    1 6amp motor on Y
    1 6amp motor on Z
    I am using Gecko Drives
    A PMDX 126.
    I am very new at this game. Will i set Mach 4 so that it never "lugs down"

    Thanks for now!
    Todd

  2. #2
    Join Date
    Feb 2007
    Posts
    4553

    Post Re: How Many Amps Needed

    Todd,

    You did not mention if you are using stepper or servo motors however as a rule of thumb Gecko suggests 2/3 of the motors combined amperage .
    If you have stepper motors on all four axis that would equate to a (16) sixteen amp power supply.

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  3. #3
    Join Date
    Apr 2014
    Posts
    11

    Re: How Many Amps Needed

    Ok thanks that makes sense. I must have missed that reading the gecko manual.

    Sent from my Moto Z (2) using Tapatalk

  4. #4
    Join Date
    Jun 2011
    Posts
    692

    Re: How Many Amps Needed

    Do you mean power from the wall outlet or just sizing a power supply for the axis motors?
    Power from the wall, I'd say 30A minimum @ 240V. 50A would be safer.

  5. #5
    Join Date
    Apr 2014
    Posts
    11

    Re: How Many Amps Needed

    Yes from the wall is what I meant. I should have been cleared on that. Also if someone could point to threads where people have worked on similar machines that would be great.
    Thanks

    Sent from my Moto Z (2) using Tapatalk

  6. #6
    Join Date
    Jun 2010
    Posts
    4252

    Re: How Many Amps Needed

    Not one person in a thousand will ever draw full power on all their motors at once.
    I would suggest, very roughly, that you are unlikely to ever draw more than 5 kW in normal operation.

    Cheers
    Roger

  7. #7
    Join Date
    Jan 2005
    Posts
    15362

    Re: How Many Amps Needed

    Quote Originally Posted by Toddler View Post
    Yes from the wall is what I meant. I should have been cleared on that. Also if someone could point to threads where people have worked on similar machines that would be great.
    Thanks

    Sent from my Moto Z (2) using Tapatalk
    The average machine like this running on 240v NA supply will need a 30 amp minimum supply at 240v, a larger supply if you have it, is always better, the 5Hp spindle can use up 20amps when run on single phase, at startup and working hard
    Mactec54

  8. #8
    Join Date
    Jan 2005
    Posts
    15362

    Re: How Many Amps Needed

    Quote Originally Posted by RCaffin View Post
    Not one person in a thousand will ever draw full power on all their motors at once.
    I would suggest, very roughly, that you are unlikely to ever draw more than 5 kW in normal operation.

    Cheers
    Roger
    You are forgetting about the 5Hp spindle, being run single phase 240v the VFD Drive needs up to 2/3 more input than output
    Mactec54

  9. #9
    Join Date
    Jun 2010
    Posts
    4252

    Re: How Many Amps Needed

    Could be a good argument for getting 3-phase from the grid installed (NOT from a rotary convertor!).

    Cheers
    Roger

  10. #10
    Join Date
    Apr 2014
    Posts
    11

    Re: How Many Amps Needed

    Yes that'd be great. It is only a quarter mile away but it would be all on my land so I don't think it'd be free..
    Thanks for all the input!!!

    Sent from my Moto Z (2) using Tapatalk

  11. #11
    Join Date
    Jun 2010
    Posts
    4252

    Re: How Many Amps Needed

    Not free, I am sure, but have you had it costed?
    I got a neighbour with a little backhoe to help me dig a ditch, then I laid conduit and 60 A 3-phase cable in it, and got the grid people to hook it up at the pole. I filled the ditch. The cost was not big, and infinitely worth it, and it is fire-proof. (I live on a farm.)

    Cheers
    Roger

  12. #12
    Join Date
    Jun 2011
    Posts
    692

    Re: How Many Amps Needed

    In the US, getting 3 phase power typically is a couple thousand $ for the install, and I think 'commercial' power ends up more expensive monthly as well.
    It is a concern though, if it's only a 5 HP VFD, running on single phase will likely derate it to somewhere between 2 and 3 HP. If you need to run the spindle at 5 HP on single phase, you will likely need at least a 10 HP VFD.

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