Re: power supply size [was: Where to buy transformers?]

My machine is an Enco mill-drill, with maybe 300lbs of tables & vises
on the table at any one time. So I'm not really expecting to hit full
load on the motors except for brief periods of time -- I was just
wondering what the experiences of others in the group were.

As to hitting the wrong button -- if the motor controller limits
voltage to the motor, then all I need to do is make sure I hard-code a
reasonable maximum feed rate to make sure I don't accidentally break
things. I doesn't take 20A to accidentally cut through my vise with
bad g-code, and I'm not hooking the motors directly to the supply, so
I'm not quite sure why a small power supply would really offer much of
a safety advantage. If I have enough power to run three motors at
moderate rates, than I still have enough power to break something with
one motor at high load, right? On the other hand, I don't want a
high-power transformer to overheat in my garage because I misjudged
how much power I require.

I'd guess that an least a few people on this list have broken
something with big, high-power, home-made chunks of spinning steel,
and I'd like to benefit from the mistak... I mean experience of
others. :-)

> It depends on the size of the machine. 14 A at 60 V is 840 W, or about
> one HP output from the motor. That is a lot of power, probably good for
> a Series II Bridgeport machine to get up close to the same performance
> as the EZ-Trak control. On a much lighter machine, you would likely
> break something or get hurt by pushing the wrong button. If you DO have
> a Series II, I would go for the 20 A transformer. If a smaller machine,
> I think 10 A will probably be sufficient. The servo drive limits

the voltage

> to the motor, so a higher voltage DC supply will not harm the motors.