Re: Gecko, fuses on the power or not ?

> Dave -
>
> Bummer on burning a drive... out of curiosity, what was the problem?
>
> Gary
>

Not Dave but I took a gecko out a few weeks ago by crashing the cutter into the vise jaw.
Not a bad smash as things go 20 to 30 thou off on a grinder will clean the jaw up and the cutter, 20mm, has been resharpened but it took the Z axis drive out.
All well fused both at AC and DC levels.
Each Gecko has a 5A fast blow and it never touched the fuse.

I was part way though a long job run so I swapped the blown Gecko for a new one, we are talking 210's here running Bridgeport type 42 motors at 68 volts and 7 amps.

Ran the job for the rest of the day and all the following day. Switched off at the nightime, came in the following morning, switched on and no Z drive, fuse OK, 68 volts to the Gecko but it was dead.

No more spare Gecko's to hand so fitted a Chinese 80 volt 7.8 amp drive and the machine is back up and running.
One thing I have noticed is that the Z axis on a long pecking drill cycle would always loose a few steps and not return to home at the end of the job, could be 15 thou out.
Never really worried me as these are all thru holes but noting I did could alter this error.
Tried leading edge, traing edge, altering pulse and dwell timing etc, all to no avail.

Since fitting the Chinese drive on, all I have done is alter the steps per inch as the Gecko is 10 microsteps and the Chinese drive is 8 but this error has dissapeared and the axis homes every time.
This machine although it was made as a CNC shares dials on it like it's manual counterpart so I can see to a 1/4 of a thou if there are any errors.

I still feel that the crash wasn't enough of a crash to take a drive out and I have no idea why the second drive went after only a day and a half.

Just time will tell how good these Chinese drives are, one thing I have noticed when looking inside is that the printed circuit from the mosfets to the screw connectors is over a 1/4" wide and very robust.

John S.

>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
> <dave_mucha@...> wrote:
> >
> > Hi all,
> >
> > I toased a Gecko last night. too late and I got sloppy.
> >
> > I was wondering what the best way to use fuses would be ?
> >
> > one on each Gecko ?
> > one main on the enclosure ?
> > some other arrangement ?
> >
> > I had a single fuse on the enclosure on the AC lines. IT was way
> too
> > large and didn't blow.
> >
> > Also, what type of fuses does one use on CNC stuff in general ?
> fast
> > ro slo blow ? something different ?
> >
> > Dave
> >
>
>
>
>
>
>
>