Re: [CAD_CAM_EDM_DRO] switching motors (was Re: motor grounding and DB9 conne...

In a message dated 28-Mar-02 07:12:44 Central Standard Time,
davemucha@... writes:

> Since this thread mentioned switching from a mill to a lathe and
> back, why could one not just wire up both and then use a few relays
> to determine which machine was being controlled ?

Dave: I assume you mean there would be steppers on each machine, and the
"electronics" would simply be switched between them, with relays, when you
wanted to change machines. This might seem a logical approach for us po'
boys, at first, but even very fine relays have more "contact resistance" than
good machined, gold-plated connectors, or, perhaps, "mercury-wetted contact
relays", if you can find 'em for the currents involved (several amps). All
my steppers are SOLDERED to wires, which are "soldered all the way" until
they get to the screw-tight terminals on the drives, which "ain't MY doin's!"
Oh, I forgot: My lathe's "X stepper" (that's the one that changes diameter
of cut, "Z" being the axis! Ain't that dum' !!!) has a 4-pin "screw-on mic
connector" with bifurcated pins and solid machined sockets. VERY low
"contact resistance", and never any problem).

Relays for such as steppers give me the heebie-jeebies! Lotsa luck!

Would be interested to read others' opinions on this point in here! Jan
Rowland


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