"I was cruising the Mouser catalogue and ran across some 20 watt Ohmite
non-inductive resistors in TO-220 cases that are described as "high pulse
tolerant" designs. Any reason these wouldn't be a good choice for Beverage
terminating resistors, at $5 each, or is this overkill?
"73, Pete N4ZR"
Pete, I used these for a number of years and was very pleased with them.
They did eventually fail, however, because even with high-energy "pulse"
ratings, the small ceramic resistor element is prone to fracturing. I have
since had much better luck using four or five 2-Watt carbon resistors in
parallel.
If I couldn't find any more of the 2-Watt carbon parts (Allied stocks a few
1-Watt values), I'd look at the Ohmite OX and OY resistors. They are high
energy density parts with a lot of tolerance for overloads. They have
low-inductance ceramic elements. And they're easy to find--see Mouser,
Allied, DigiKey, etc. Paralleling several of them would give you hundreds
of Joules of energy-handling capability.
I haven't used these on my Beverages yet (found plenty of carbon parts at
Dayton), but I have used them in several pulse applications at work. I've
also found that the Ohmite 35J and 30J high energy wirewound resistors are
very tolerant of impulse overloads. They'd be a little more inductive,
though. You'd have to take some steps to deal with this because the
commonly-available values would make it necessary to use them in series.
73,
Brad, KV5V
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