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  1. #1
    Join Date
    Feb 2010

    Rotary Phase Converter or New Drives ...Advice Needed

    I have a Tree Journeyman 320. I converted the electronics over to Dynamotion and ran it on 3 phase without a problem.
    I have two items that have taken place that bring me to a point where I'm a bit lost.

    1) My X axis started to violently shake if I brought a rapid motion to a stop too quickly. I didn't have time to sort it and identify if the problem was in the Getty N360 drive, the gould servo motor, or my less than professional tuning of Dynamotion.
    2) I lost access to 3 phase service when I needed to move the mill from work to my garage. So now I need to either convert the drives to something more modern or buy a rotary phase converter.

    I'm already driving the 2hp spindle with a VFD (220 single phase input). This only leaves a few things on 3 phase: a small lube pump, and the 3 axis drives.
    The system currently has three drives-
    Gettys N360 1/2 wave 240 VAC max, 3 phase 60 Hz; 12.5 A
    Gould permanent magnet servo Model: M113-A1.0K-900A;
    Back EMF Ke 34.2 V/KRPM; Current Lc Stall 12.5 amp.
    The motor doesn't list a torque.
    Based on the above information how do I calculate the power requirement of the 3 drives
    If I multiply by the square root of 3 (1.732) to convert from 3 phase to single phase ...1.732 x 12.5 amps = 21.65 amps per drive ...*3 drives = 64.95 amps using a phase converter on 220 single phase. and yes I will need to add the spindle at 6.2 amps * 1.732 = 10.7 ...for a total of 76amps on a 220 single phase circuit! IF I only drive the XYZ axis (not even the spindle) and I get 65 amps.
    Meanwhile, the Manual says connect the machine to 3 phase 220 and 30 amp line ...which means 51 amps on single phase. Both answers cannot be correct.

    Alternatively, how do I size replacement drives. for this machine? I may find myself doing this if the X axis cannot be cured by tuning. Any suggestions for drives and motors?


  2. #2

    Re: Rotary Phase Converter or New Drives ...Advice Needed

    This might be worth a read through. https://www.cnczone.com/forums/servo...half-wave.html
    Jim Dawson
    Sandy, Oregon, USA

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