Re: blown Gecko - shorted output ?

Hi Lee,

I don't know if the Gecko's are multi layer or just 2 sided. I think
they are 2 sided so I can see all the traces.

I did ohm the drives, coil to coil and coil to frame as well as coil
end to end and end to center (6 wire) it looks correct. completley
open except for coil end to end and end(s) to center.

I even ohm'd it from the Gecko terminals, coil to coil, end to end,
and each line to power supply case and each line to machine frame.
And I did that each time to make sure when connecting I didn't miss a
strand from terminal to terminal.

The only thing I didn't try was to power the coil to 35 volts then
checking if it is arcing coil to coil or coil to frame.

I know Mariss does like to do forensic review and I did send him 4
units. unfortunatly, my timing is bad. as you know he just got his
new toy up and running and I'm sure his attention is squarely on
getting that into production. Cash in the door is better than
finding some odd problem.

Dave





--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Lee Studley
<indigo_red@q...>" <indigo_red@q...> wrote:

> Hi Dave,
> I hope it's not one of those situation where,
> the "drive blowed up real good" but didnt show it, then took out
> the previous motor tried afterward. If you can, ohm out all the
> motors again coils and to the motor case.
>
> Those look like the early G201's, I wonder if the anodizing used
> as insulation on the Gecko backplate on the mosfets may have
> scratched thru by vibration and failed. Its sorta hard to tell
> after the fact, but Mariss may interested in a postmortem.
>
> At this point, I'd try out the motors with a surviving G201 as
> another reality check. On the bench isolated .
>
> (Sounds like you have this already covered)
> And put a *big* 10ohm resister or a smaller car headlight in series
> with the power supply and the drives till you get it ironed out.
> This should help protect the drives and still deliver usable

current

> at low loading. Also try remounting the motors, but leave the
> belts/couplers off for no loading.
>
> -Lee
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude
> <davemucha@j...>" <davemucha@j...> wrote:
> > Hi Lee,
> >
> > One thing that bothers me is that it ran on a NEM23 for months
> before
> > I switched to the Nema34's.
> >
> > now nothing seems to work. I figured it was a bad motor so

switched

> > back to the NEMA23 and pop. as you might imagine testing with

new

> > drives is not fun or cheap.
> >