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Re: [TowerTalk] Pipe with water

 To: Red ,TowerTalk Re: [TowerTalk] Pipe with water Jim Lux Wed, 12 Jul 2006 21:35:44 -0700
 ```At 08:51 PM 7/12/2006, Red wrote: >Hi, Gang; > >I scribbled a few calculations concerning the temperature rise if a >copper pipe filled with water conducts a lightning strike. > >I assumed a 0.5" OD pipe with 0.050" wall thickness and I assumed a >30,000 A current for a duration of 1 millisecond. That makes a worse >than average strike. looks basically sound to me. This is actually not a lot different from the water resistors used in HV pulse power applications. I've built various sizes as things like charging resistors for a marx generator, as well as the load dump. http://home.earthlink.net/~jimlux/hv/rwater.htm has some similar calculations to yours. I would suspect that electromagnetic forces might have a bigger effect. The fast pulse at high current can put pretty high forces on the pipe. It's a real design issue for bus bars in electrical substations for instance: you don't want things breaking during a fault. Heck, even the regular 60 Hz current at several thousand amps puts a pretty impressive force on the bus bars. F = 2E-7 * I1*I2/r Put, say, 10 kA on the two buss bars, and have them 50 cm apart, and you're looking at 1000 N (about 200 pounds). Put a 100 kA transient from a fault into the system, and you're looking at 100kN. (and therein lies the secret of shrinking a quarter to smaller than dime size...) Jim _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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