Re: [CAD_CAM_EDM_DRO] stepper size

In a message dated 8/18/00 12:40:57 PM Central Daylight Time, salterc@...
writes:

<< I am building a 3 axis plasma cutter, the controller I am looking at
will supply 1.25 A per phase. will that drive a large enough motor, I
want the table to be 4' x 8' . Or does anyone know what size motor I
need and what controller would work. >>

Chris: first, I assume a "plasma cutter" is something like an oxy-acet.
torch cutter, that is, there is very little "cutting-tool drag" contributed
to the load on the carriage moving screws, linear-bearings, etc. I have
experience building (from scratch) woodworking "X-Y tables" moving a 4 hp. HF
router-motor about, and this "cutter load" was considerable, of course.
However, the "iron" of the carriage, etc., was considerable, as the machine
covered a like large area (but about 5' x 10' in this case), and for that,
there is absolutely NO way a 1.25 A/phase stepper can move such a load, even
"slow as a clock"! You can find only NEMA Size 23 motors for that low a
current! You will need AT LEAST Size-42 motors, even if you build it as fine
as an astrophysical instrument!

You should realize at the outset you will need a state-of-the-art "bipolar
chopper" drive for each axis. The Superior Electric division of Warner Dana
(I give you a link, below) make suitable drives and excellent steppers.
Expect to pay serious change for such!

Lotsa luck! Jan Rowland, Troll <A
HREF="http://www.warnernet.com/sem_prod.html">Warner Electric SLO-SYN Product
Overview</A>