"Richard J Kinch" wrote in message
. ..
Ken Sterling writes:

A fella runs a junk yard and has a crane with an electro-magnet for
moving scrap metal - he uses a 10,000 watt DC generator to power the
magnet.

Someone might have abstract ideas about doing this by rectifying an AC
generator, or a similar scheme. But 10 KW is a lot of power and it isn't
so simple to just hook up a few parts and have it work for long. Does
this
thing really use that much ooomph? Where does all the heat go?



Richard

40 amps at 240VDC may be about right for a big magnet. I've fixed my
buddy's magnet several times. It runs from a BIG engine driven welder. It
draws over 80 amps at 70 VDC and it isnt a very big magnet. I never thought
about how warm that magnet gets. I'll sure feel it next time I see it
working.
I'm not skilled at making rectifiers but, I'm confidant that even I could
build an adequate rectifier for this magnet since all the switching devices
are already there for the controls.
I was considering suggesting that the guy who is looking for the DC source
for that magnet, might be able to save some $$ by finding a military surplus
400 Hz 3 phase 208 VAC power source, since they are much cheaper than 60 Hz.

Jerry