"PrecisionmachinisT" wrote in message
news:V9mdnb2LPYSnUjPTnZ2dnUVZ_oidnZ2d@scnresearch. com...

wrote in message
...
So I'm probably buying a used Fadal mill. It is currently wired for
480 volts. The shop it is in uses an inverter to convert the incoming
240 single phase to 3 phase which is then sent to a step up xmfr and
then to the mill. The RPC maker is no longer in business so I can't
ask them if the RPC I have can be connected to the xmfr. Can this be
done? I think I can re-configure the mill to run on 240 volts but I'm
not sure. Furthermore, there are already wires in my shop that can
supply power to the Fadal but I think the gauge might be too small for
the amperage draw if the Fadal is wired for 240. Adding wire would be
kind of a pain as I would need to pull wire through about 40 feet of
conduit. I can do it but it's a pain plus I would need to buy 180 feet
of wire because the machine is 3 phase and there is another 15 feet of
wireway the wire needs to go in. The wireway is the kind where you
just remove the covers and lay the wire in. The conduit goes from the
wireway up the wall 18 feet up, across the building, and then down
the wall to the wireway on the opposite wall.
Thanks,


Every Fadal I've ever seen except for thew single-phase models has a
built-in multi-tap transformer inside of the rear cabinet which allows
connection to any mains voltage between 190 and 510 volts.

That said, unless your phase/phase voltages are all within 5% or so of
each other, you may need to rotate your phases so that the 100v AC bus
isn't low because this may cause problems with relay chatter, sluggish
carousel rotation and so forth.

Other thing is IF it has rigid tapping, and your wild leg is more than 5%
above /below the others, then there is parameter setting you need to take
a look at and correct if necessary...otherwise it will affect the spindle
accel /decel time constant possibly causing breakage of small diameter
taps and overly loose fits on the larger ones.


I guess I should add that I have 3 fadals here, two are 3ph I run both of
those pretty much all day 5 days a week off of an RPC and only rarely is
there a problem.

In any event, you want to make absolutely sure that in the event of a
momentary power outage, your rotary unit will shut down and that it will NOT
try and restart by itself

--otherwise, you are risking serious damage to the equipment...and even so,
you will still want keep set of spare mains fuses and a backup surge
supressor card and / or some 250vac rated varisters on hand.

The proper fuses are class RK1, ( fast acting ) and if you replace them with
a different variety or if you permanently remove your surge supressor card
then you are a blithering idiot.