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Old 13th December 2012, 06:02 PM   #1
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Default Dummy Loads

Any opinions on how well these would work? I am thinking about buying 8 of them, it would only be 400 watts worth but at short tests I am sure they could handle much more?

8 Ohm 50W Watt Ceramic Tube Wirewound Resistor Fix | eBay

Maybe these would be better?

http://www.ebay.com/itm/Ceramic-Tube...item51a48f8ac4
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Old 13th December 2012, 06:39 PM   #2
AndrewT is offline AndrewT  Scotland
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Might be cheaper and certainly easier to use by stringing together 5W wirewounds.
Buy a hundred or two at the best discount you can find.

4 off 10r strung together in series for 40r and then 8 strings in parallel for 4r0 @ 160W.
build 4 or six of these for dummy loads.
2 in series for 8r0 320W.
2 in parallel for 2r0 320W
4 in series/parallel for 4r0 640W
6 in series/parallel for 3r33 or 6r0 960W

I used 3 off 20r series for 60r, then 15 parallel strings for 4r0 @ 220W.

180 resistors gave me 4 dummy loads.
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Last edited by AndrewT; 13th December 2012 at 06:56 PM.
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Old 13th December 2012, 07:20 PM   #3
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I use two of these myself. Not cheap but I found a deal a long time ago so I went for it and bought two of these.
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Old 13th December 2012, 09:57 PM   #4
ultra is offline ultra  Greece
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Default resistive load

i use these four resistors, 250w/4Ω/1% each
and i can parallel them using copper bars.
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Old 14th December 2012, 07:59 AM   #5
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THIS type of resistor is very durable and requires no heatsink to meet it's power spec.

Use the mounting clips or hang them on wires (strung through their core). Either will allow you to use a fan to force air over the resistor and through its core (for additional cooling). I use two in series to produce a 4 ohm load and add additional 4 ohm pairs with switches to produce the desired load. I've run very large amps on them that could produce 3-4 times their power rating and have never had one fail. I generally test with music. If you used a continuous sine wave for long term testing, you may need to be a bit more conservative.
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Old 14th December 2012, 08:49 AM   #6
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Audio Power Amp Amplifier Dummy Test Load 4 Ohm 300W | eBay

These ones say they have been ran 16 times their rated power for 5 minutes with no visible flames.

Thats 4800 watts. Read the specs at the lower part of the page and let me know what you think.
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Old 14th December 2012, 08:57 AM   #7
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588-C300K4R0E Wirewound Resistors - Chassis Mount | Mouser
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Old 14th December 2012, 08:59 AM   #8
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Quote:
Originally Posted by Perry Babin View Post

If I was to buy 4 of these and used 4 fans could they handle a good duty cycle?
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Old 14th December 2012, 09:02 AM   #9
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Click the image to open in full size.

My god thats a whole lotta business there!!!!
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Old 14th December 2012, 09:13 AM   #10
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The image didn't load.

I don't know what you're testing but unless you have a huge power supply or bank of batteries, you're unlikely to damage the 300w resistors. You only need one fan. Mount them so that their ends are directly in front of a 120mm fan and the air blows through them. A 100CFM fan should be enough. If you want to get a bit crazy, you could buy the 9cr1212p0g03 fan. Of course, you'd have to ear ear plugs when it's on. I purchased one to see what it was like and it's insane (for lack of a better word).
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