elderly bus cables
elderly bus cables
(OP)
i got an 18000 amp per leg ac electric arc furnace with bus cables over 3 years old with tens of thousands hours running time, our bus cable provider suggest we swap them out every 9 months or at 20% increase in resistance, which got me wondering, 20% increase of a cable newly rated at 0.033milliohms could cause some power problems, right?
say, 20% for each of the three legs at 18000 amps
p = (18000^2)*(.000033/.2) = 53460W
ptot = 53460 * 3 = 160.3kW
is that very bad figuring or very bad cables?
say, 20% for each of the three legs at 18000 amps
p = (18000^2)*(.000033/.2) = 53460W
ptot = 53460 * 3 = 160.3kW
is that very bad figuring or very bad cables?






RE: elderly bus cables
Swapping 18,000 amp cables every 9 months is a powerful financial incentive to look for an alternate solution.
Thanks
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: elderly bus cables
RE: elderly bus cables
area for this forum!" and scroll down, you will find instructions on posting pictures, thanks to itsmoked.
Is the heat high ambient temperatures and radiated heat or because of high current densities?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: elderly bus cables
am i doing the math correctly for energy lost?
RE: elderly bus cables
P = I2 x R
P = 18,0002 x (0.000033 + (0.000033 x 0.20))
P = 12.8kW
Unless I screwed it up..
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: elderly bus cables
When the cable provided says replace them every 9 months, thats a red flag to me, I am guessing this size cable is not cheap.
RE: elderly bus cables
thanks guys, yeh its about 12k for a decent new one, i now see where i went wrong with my math, thanks
i am going to measure the resistence this weekend and will report my finding because theres the chance for some intresting numbers pouring out
RE: elderly bus cables
Put 50A DC thru the cable and measure the voltage drop?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: elderly bus cables
Is the current stable enough to use the voltage drop under load to determine the resistance?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: elderly bus cables
Can I watch you skinny down that,(RE1), cable into the vat of boiling steel, and hold the meter probe on the connector?
RE1: Regularly Exploding (cable)
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: elderly bus cables
Actually, I may try to get my last helper to do it when he wakes up.
The boy was not happy to see this posted on the office wall the next morning. I didn't particularly care that he was not happy.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: elderly bus cables
Wheatstone bridge, thats exactly the type of application it is for.
RE: elderly bus cables
I think you need Water Cooling Cable.
See http://www.watteredge.com/pl/order_wccd.htm
Best Regards