Re: Gecko, fuses on the power or not ?

Hi John,
What chinese drive, if you don't mind me asking? Website? Anything?

Thanks!
/Henrik Olsson.

> 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.