[Amps] Bird 1KW+ Load Resistor/possible danger !

[Pat Barthelow]

I have a good old reliable dummy load, as shown in the picture:

http://groups.msn.com/TUVAORBUST/rfparts.msnw?action=ShowPhoto&PhotoID=5

I havent looked into how one replaces or checks the cooling oil, but this particular load is probably
30 or 40 years old.  Possibly a high chance that it has Old style transformer cooling oil.   No leaks.
If I or anyone else should look into the oil filled coolant chamber for whatever reason, is there any
telltale smell or coloration that will be a clue to whether the oil has PCBs?


Another question,  The dummy load in the picture is rated (probably conservatively) at 600 watts
continuous.  I have seen duty cycle curves on other dummy loads that tell you what the shorter term
limits are Power vs Key down time.   The graphics look very similar, an exponential curve.
At some point though, very high power applied to the load might put so much instantaneous heat
into the load resister that it cant transfer to the large oil bath, and fail, or change vale
Any idea what the say,  30 second power rating  would be roughly for  this dummy load.  I have
put for short terms  about 1.2 kw  into it without prolems.

All the Best, 73,
Pat Barthelow aa6eg at hotmail.com
http://www.jamesburgdish.org
Subscribe: http://bambi.net/jamesburg.html
Jamesburg Earth Station Moon Bounce Team

> From: la7sl at online.no
> To: amps at contesting.com
> Date: Sat, 17 Nov 2007 17:45:26 +0100
> Subject: Re: [Amps] Bird 1KW+ Load Resistor/possible danger !
>
> POSSIBLE DANGER !
> Coolants like the one you describe very frequently contained high
> amounts of PCB ! This is a hazardous group of chemicals
> that is now to be treated as very dangerous waste!
> It can affect several important functions in your body, even at low
> concentrations. It accumulates in your body, it accumulates in the
> food chain and stays in our environment. It may affect your reproductive
> capacity.It may cause cancer. Stay away from that stuff,- deliver it to a
> suitable reception site. Wash your hands and wear gloves. I am NOT
> kidding ! I am not saying that it DOES contain a PCB,- but those chemicals
> were frequently used in coolants for such purposes, as well as in
> transformers
> and oil filled caps. Whatever you do: do not throw it in the waste bin.
> Aside from environmental pollution, it could get you a USD xxxx fine if
> discovered !
> LA7SL
> Peter
> ( I love nature,- but I am not a freak...)
.
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