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

[Roger]

>
> 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?

PCBs will typically have a sharp smell while the safe stuff smells 
like...oil such as castor oil, mineral oil, or motor oil. Silicone oil 
normally has no discernable odor, but it 's doubtful it would have been used 
that far back. OTOH some outfits were using it in top end equipment and 
although it seems like a long time we were already aware of the PCB problems 
around 30 years ago.  BTW It only takes one whiff/sniff to know if it's not 
regular oil and you don't have to get real close.

It's not good for us or the environment, but it's not a panic situation 
either.

73

Roger (K8RI).

>
>
> 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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