CAD CAM EDM DRO - Yahoo Group Archive

G201s repaired, now to bring up machine

Posted by Chris Brick
on 2003-04-09 12:53:27 UTC
Hello all,

I've repaired two of my dead G201s, thanks to Mariss and others on this
list.

It seems that the same pair of FETS blew on all 4 G201s. This is the
pair that the capacitor attaches to on the top of the board. Is this
phase weaker than others or is this a sign of problems somewhere else.
Three separate motors and two sets of motor wires have been connected
when failure has occurred. I'd doubt that all three of my motors are
damaged in the same exact manner, especially with the coils all reading
the same on the ohm meter.

In order to avoid blowing things up again, I'm hoping to put some things
in place to help keep the current down while I focus on finding the
problems.

Last night I checked the motors with an ohm meter and all the windings
read 1.2Ohms. When I turn the motor they change and then come back to
1.2 and hold. I checked the cables and connectors for shorts/breaks and
all are fine. I'd like to limit current between the motors and Geckos.
Back when I had a brain, I remember doing this with resistors. Is this
still the preferred method?

I've got a 24V @16A switching PS with a 3700uF 450V cap I've been using
for bench testing. I'm wondering if I should use this power supply for
initial testing once I get the machine back together? Is the 3700uF cap
going to give me enough leeway for the current to catch up when I start
moving motors? I've been using the 57.6vdc transformer/bridge/cap combo
for all testing and part smoking sessions in the past few weeks. I'm
hoping the 24V will help minimize any more damage if things are still
not working correctly.

Thanks again for all the help. I'm continually amazed at the level of
knowledge and patience exhibited on this list.

Cheers,

Chris

Discussion Thread

Chris Brick 2003-04-09 12:53:27 UTC G201s repaired, now to bring up machine Mariss Freimanis 2003-04-09 14:05:11 UTC Re: G201s repaired, now to bring up machine Chris Brick 2003-04-09 14:14:47 UTC Re: [CAD_CAM_EDM_DRO] Re: G201s repaired, now to bring up machine jmkasunich 2003-04-10 13:42:07 UTC Re: G201s repaired, now to bring up machine Chris Brick 2003-04-10 14:58:01 UTC Re: [CAD_CAM_EDM_DRO] Re: G201s repaired, now to bring up machine