Re: [CAD_CAM_EDM_DRO] Gecko burned - fixed for now

Les Newell <lesnewell@...> wrote:

Hi Keith,

Your symptoms sound very similar to my Z axis. It was always a bit
sluggish and had to be tuned slower than X and Y. After a couple of
months use the Gecko popped. After checking everything I replaced the
Gecko and it worked fine for another couple of months before blowing.
Twice was too much for me and I am replacing all the motors with servos.
Shoulda done that in the first place. I hate steppers...

/// From reading about steppers and servos it seems that steppers merely move when told to and do not sense a load and draw more current to overcome it, they skip and lose position instead when confronted with a higher torque requirement. Steppers are all about holding stationary position and not big on traversing to a new one. Servos on the other hand sense a load and draw more amperage to overcome the load and thus hold position at higher torque requirements. Is this accurate? My Bridgeport originally had steppers on it. Only 2 of the three worked reliably and one of them skipped incessantly. During the retrofit I switched to servos and there is no comparison. Rapids of 120 ipm and never loses position. I sold the steppers on Ebay for what the servos cost from the same. An even swap with a huge gain.

Ron


/////
Fuses are pretty useless when it comes to high current spikes. If you
have a fault the fuse is not likely to save the transistors though it
will probably blow before the tracks so the Gecko will be repairable.

I initially had 5A fuses on my X and Y but they had a tendency to blow
sometimes when making sudden rapid moves (high acceleration). If I
recall correctly I have 8A fuses in there now.

Les





---------------------------------
Do you Yahoo!?
Check out the new Yahoo! Front Page. www.yahoo.com

[Non-text portions of this message have been removed]