Bridgett update

First a warning, this is about big iron and fast rapids so if that is
offensive to you or generally intimidating please skip reading this post.

I just bolted a big old e-bay special NEMA 42 brushed servo motor onto the X
axis of Bridgett (Bridgeport series II). Connected it to a Gecko G320 and
used a 62 VDC power supply. Rapids are rock solid at 150 ipm!! I know, many
of you are tired of hearing about the Gecko drives, but every time I hook
one of the step and direction servo units to a machine I am blown away with
the performance improvement from a stepper. All I can say is try it, you'll
like it.

An interesting story on the E-bay servo motors. Then came with some real
nice 500 line encoders with ball bearing shafts and one of those real slick
factory mounts to the servos using a helical coupler. When I hooked them to
a scope they seemed to be working fine. I then hooked the motors to the G320
and fired it up and the servos would stabilize and then jump suddenly then
stabilize again. Motion was the same way, smooth, then some jumps and
lurches and then smooth. I pulled the encoders and used some duct tape to
attach one of the Electronic Goldmine mini-servo motors with 1000 line
encoder to the shaft where the original encoder was. Wired it up and turned
it on. The servo stabilized just fine (considering how loose the connection
was to the encoder) and motion was very smooth. Diagnosis was that the
encoders that looked good on the scope have a loose connection somewhere in
the electronics. I then ordered a set of US Digital E2 encoders with a 250
line resolution and they bolted on very nicely with just a tiny bit of
handiwork on the holes of the mounting ears. Fired up the drive and it is
stable as can be and performing great. The encoders cost me as much as the
servo motors, but for $90 including the encoder I don't know where I could
have gotten a servo suitable for a series II any cheaper (or get another one
for that matter).

Tim
[Denver, CO]