Original poster: Tom Perigrin <tip@xxxxxxxxxxxxxx>
At 08:56 PM 1/9/2007, you wrote:
Original poster: Mike <megavolts61@xxxxxxxxx>
You can't get cheaper and simpler than some saw cuts and
electrical tape.
-Phil LaBudde
(save your time and money for the IGBT's)
Although I'm a big advocate of going cheaply as possible, I'd have
a problem with the visual asthetics of this idea when spending
thousands on what is a showpiece.
More than that... consider the power going through the coil.
Consider what happens if those saw fingers only contact the next
section of pipe at a few places, with a little copper oxide in
between the two layers of copper metal, giving a resistance of 1 ohm
for each joint. The current flub through a joint of 1 ohm and 10
square mm is going to be "fun". Also, as the copper heats it will
oxidize even faster, giving us the sort of problem we see with a
poorly fitting terminal on a car battery. Heck, I've seen that sort
of problem with the poorly made plug on my Chinese Air Conditioner...
after 1 year of use I unplugged it and was scared to death by the
amount of carbonization evidenced around the prongs.
I'd suggest getting a plug and socket made for each joint. The plug
and socket would consist of a 4" OD taper by about 12" long. These
should be accurately turned to be +/- 0.001 (or better). Then, get
them gold plated with at least 0.005 of 24K gold. Also, there
should be a mechanism like a pipe union that snugs the joint
together. Clean the joints with warm soapy water before each
use, and make a protective covering for transport. That's not going
to be a lot of gold..
Sound like MIL-SPEC ? Yeah, probably... but when you are working
with something like this, it's better not to screw it all up by
trying to save a few bucks on such a critical part.
Failing that, I liked the previous suggestion of Stainless Steel
inserts... those can be wire brushed with a brass brush before
assembly to assure there is no oxidized layer contributing
resistance. I don't think you should use copper on copper, unless
you implement a strict protocol of having each joint thoroughly
cleaned and degreased before each assembly.