Wire Wound Resistors for Pulse Power Applications

Yes, of course, but for some reason I'm too lazy to do the calcs.

Why wouldn't it be?

Maybe if one examined all possible combinations (including material), there might be some length:diameter ratios that were unrealistic. However, the right length piece of 12-gauge copper can fix the OP right up.

P=I*I*R gives 800 Watt. That's less than 1.0kW, so passes the sanity check.

800 Watt is similar/lower than most (old style wire would) electric jug elements, so passes the "I've seen something in that realm" test.

Probably your biggest challenge is going to be finding a wire material with acceptably stable resistance across the temperature range it will encounter.

I would like to know why you think the manufacturing of this resistor might not be possible? Your question implies an unstated concern and I'd like to know what that is. Did you ask this of a manufacturer of sub-watt resistors and they said, no? Are you concerned with how hot this resistor will get and the change in resistance this temperature change will make? Are you worried about the lead bonding with temperature? Maintaining low inductance? What?

They did use these on golf carts for speed reduction. Until they cam up with an electronic speed control. Most had movable taps for the resistance adjustment. i have seen them up to 2000 watts.

http://www.andymetals.com/windows/b1.sb1.1.htm

Here. Google this part number: PFE5K2R20E

This is for a 2.2 ohm resistor rated for 745 watts at 18.4 amps. The company is also willing to make runs of non-standard values for a price of course and up to 1,600 watts.

If you can buy something like this:

...why do you think you can't buy something so small?

The real trick is the non-linearity of the resistance as the temperature rises, but proper material selection can easily overcome that.

Oops, forgot to mention to make sure that you specify specially wound resistors to minimize the potential additional effects of inductance, especially important in pulse duty.

http://www.globalspec.com/learnmore/electrical_electronic_components/resistors_potentiometers/wirewound_resistors

Is that a piece of wire of some length and diameter which happens to have resistance 2 ohm, or what?

Assuming DC, volts = 1000/20 = 50, required resistance = 50/20 = 2.5 ohm. But that could be a certain length and diameter, or say 10x longer and bigger. It doesn't follow that any particular combination (giving 2.5 ohm) can dissipate 1 kW without overheating. You need to think about it a bit more.

Any feedback from Mr., Ms., or Mrs. Anonymouse?

Hi!!

Thanks for prompt response!!!! I didn't expected it.

That current rating was a typo continuous current "~22.5A"

My application is to limit the arc current in a microwave tube. The nominal current is ~50A to 55A @ -55kV. Now as a passive protective measure, I'm considering to limit the arc current so that my crowbar can work. Required(Intended) values, 0.5Ω to 4Ω in steps. For this I'm considering 2Ω units as basic elements. With which I can achieve 0.5Ω to 4Ω values.

For this, I wasn't sure whether it would be easy to manufacture resistor unit?

with my following concerns

• Such low value resistance and higher wattage?
• Non-Inductive nature(What would be typical L/R ratio)
• What would be the surface temperature rise ?
• What would be maximum potentials they can withstand? (electric stress during arcing/short circuits in tube)
• Probable de-rating in performance

I'm new to this forum.

You arenow at a stage where you should beasking the fabricators rather than this general forum.

What you are seeking is feasible in an engineering sense.

The fabricators will be able to tell you the specific details you seek if they already have a stock "line" close to your needs, or else they could make one to your needs for those parameters.

They would also be able to recommend the mounting hardware required.

This mob seem to have the type of thing that you are looking for (http://mf-powerresistor.com/non_flam_rpw.htm) with a phone and e-mail contact. One of many that come up when use www\\ enquirey.

I was under the impression these high voltage low inductance resistors were available.

Have you tried an online search and a search of the resistor manufacturer websites? Also, the major resistor manufacturer websites are generally good at supplying the data you are requesting (in datasheet or application note or book form).