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[Amps] 20kw Dummy load?

To: "amps@contesting.com" <amps@contesting.com>
Subject: [Amps] 20kw Dummy load?
From: Will Matney <craxd1@ezwv.com>
Date: Sun, 15 Aug 2004 10:43:13 -0400
List-post: <mailto:amps@contesting.com>
Robin,
Lo and behold, God help me for telling this one. You might just try using saltwater in a tank for that load you need. I seen a dummy load built with two electrodes sticking in salt water. The water was made conductive enough by adding enough salt to (saturating) the water with periodic checking of it resistance. I actually seen one made in a "Mason Jar" for a low power amp of a few hundred watts and it worked. Now lets suppose you used something like a 50 gallon steel tank, using the tank itself for one electrode. Add the water and a bunch of salt until you started getting around the correct resistance, or you can move the electrodes around closer to adjust the same. Now not being joking about this at all, it really could work, the only problem would be the testing without blowing up that expensive amp! Plus I had to tell this, just could not resist it no more.


Now for my preferred route. Buy you some "Carborundum" tubular resistors. They are non-inductive.They figure the power rating for one minute X10 (100 watt, 8") if submersed in oil or water cooled is longer. You would need 20, 1000 ohm, 100 watt resistors in parallel to do what your wanting to. Kanthal Globar makes these tubular resistors in sizes above 100 watts. There's a 24" long, 2" dia. one with a rating of 1Kw. The resistance range is 1.0 to 600, part number 892-SP. It also has a 22 Kv rating which is more than you need. Your rating would need to be at least 1 Kv. So, you might use two 100 ohm, 1000 watt resistors in parallel, with oil or water cooling to do what you want. Oil for about one minute and water for some longer.

http://www.globar.com/ec/tubular.php.html

There are "planar" style resistors which are heatsink mounted. Ohmite makes these with a 1000 watt rating.

http://www.ohmite.com/cgi-bin/showpage.cgi?product=tap1000_series

Keep in mind that the voltage rating must be met too! These planars are rated for 2000 Vdc max. You might as well just build one as you'll be needing it if you keep that amp often.

Will Matney
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