Re: tape-O-matic

Brad Heuver wrote:

> I'm also trying to get an idea if
> there is ANYTHING that should be salvaged from that control cabinet;
> power supplies, amps, etc...

Well, the servo amps, if they have reasonable bandwidth and take +/- 10 V
velocity commands, should be usable. They probably use a DC main servo
supply, so the 3-phase power transformer could be replaced with a single-phase
to simplify the power wiring. (It is possible with such an ancient beast that
they use SCR phase-controlled servo amps, which will have a bandwidth
of 10's of Hz, max, and should be replaced. EMC essentially requires the
velocity servo amps to have higher bandwidth than the servo loop rate,
which you'd like to keep fairly high, at least 1 KHz.)

> Would I also be better off changing the
> quantizers over to quadrature encoders?

I think, from a description in response to your original post, that they ARE
quadrature optical encoders, but of coarse resolution. If you want .0001"
resolution on your system, you would want something like .000025" encoder
resolution. I'm running .00005" encoder resolution on my X and Y axes
(1000 cycle/rev encoders, x 4 quadrature counting = 4000 counts/rev, x 5
TPI screws = 20000 counts/inch = .00005" / count) and it works pretty
well, but I wouldn't want any less resolution.

> Back in 1995 I just wanted a
> small lathe to make jack shafts and the like to make disc sanders and
> such for woodworking. Since then, the chips have gotten harder and more
> magnetic, and I've made much less actual stuff, and filled my shop much
> fuller than was ever intended. Who knows where it will stop...

Stop? It WON'T stop - but your shop will get fuller...

Jon