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Re: [Amps] KW Dummy load resistors?

To: James Colville <jimw7ry@gmail.com>
Subject: Re: [Amps] KW Dummy load resistors?
From: Roger <sub1@rogerhalstead.com>
Date: Fri, 19 Feb 2010 01:38:15 -0500
List-post: <amps@contesting.com">mailto:amps@contesting.com>

James Colville wrote:
> Mouser has these:
>
> http://www.mouser.com/catalog/catalogUSD/641/670.pdf
>   
I like the 600 watt and 1000 units meant to be mounted on heat sinks. 
They are not inexpensive, but when compared to other high power 
resistors they don't look terribly expensive. They are also small enough 
to build a high power dummy load that'll go past 2-meters. However it'll 
take some good heat sink compound to make them reach their power 
ratings. Like the high power transistors, the problem is getting the 
heat transfer good enough to lower the delta T to the point where they 
can really work.

It looks like a pair of the 600 Watt, 100 ohm units in parallel would be 
close to half again the heat transfer area for one of the 1000 watt 
units. 13.6 sq in  for 2 100 ohm, 600 watt units Vs 9 sq in for one 1000 
Watt unit. = 51% increase in contact area. $227 compared to $142. I 
think I'd opt for the more expensive approach with a big heat sink and 
good fans, or water cooled heat sinks using cold water.

73

Roger (K8RI)
> They also have others. See their catalog pages 656 to 670.
>
>
> 73
> Jim W7RY
>
>
>
> On Thu, Feb 18, 2010 at 7:08 PM, R. David Eagle <kb8nnu@yahoo.com> wrote:
>
>   
>> Hello all....
>>
>> I was wondering if there is a good source of resistors out there that could
>> be used in building a dummy load that will handle a KW....????
>>
>> Any suggestions welcome
>>
>> Thanks,
>>
>> Dave
>> KB8NNU
>>
>>
>>
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