Re: Bridgeport retrofit servo questions

No...for a few reasons...and take with grain of salt because I am no
expert ~ learning here too!

1. the shaft size of the motors I mentioned is .625". The hole in
that encoder is only .25".

2. the shaft of the motor is 1" long. You need an encoder with a thru
hole option for the shaft to poke thru. You may also need an amp for
the encoder (as mentioned on US Digital) if the leads are longer than
2 meters (doubt it) when using an open encoder.

3. That encoder only gives you 200 lines per rev. If used on a BP
with 1:1 gearing, there may not be enough lines on the encoder to get
tight tolerance. If you increase the number of lines, the servo can
be more precisely governed. Now...just for an anaolgy, if you changed
the belt ratio to let's say 4:1, then the motor would have to turn 4
times for each turn of the screw (actually 20X/1" if using .2"
pitch)...therfore one turn of the pulley @ 1:1 might move the
axis .2" where a 4:1 would move it only .05". You can imagine how
much movement the motor would have between encoder lines if run
1:1...this is why Les suggested running a higher line encoder so that
the distance between the 2 lines is smaller ~ resulting in less slop.

Does that make any kind of sense? Again...don't take this as
gospel...I'm in the same class as you! (the one in the back throwing
paper airplanes)

-Brady

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Luke1027 <luke1027@p...>
wrote:

> Brady,
>
> What about the encoders off this motor?
> Buy the motor, pull the encoder, and discard the motor....
> would it work?
> http://www.surpluscenter.com/item.asp?

UID=2005011818310844&catname=&qty=1&item=10-1834

> I am very limited on electronics ... but trying to learn fast to

convert

> my BP to servos.
>
> Luke
>
> braidmeister wrote:
>
> >.... and it has a
> >long enough rear shaft to mount a number of encoders. Looks like

one

> >of the US Digital ones will work nicely. ...
> >
> >-Brady
> >
> >
> >