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

To: amps@contesting.com
Subject: Re: [Amps] Bird 1KW+ Load Resistor/possible danger !
From: Ian White GM3SEK <gm3sek@ifwtech.co.uk>
Reply-to: Ian White GM3SEK <gm3sek@ifwtech.co.uk>
Date: Sat, 17 Nov 2007 23:09:53 +0000
List-post: <mailto:amps@contesting.com>
Pat Barthelow wrote:
>
>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?
>
No leaks, no hazard.

However, I have occasionally borrowed one of the larger Bird loads which 
had been filled with PCB. When PCBs began to be seen as a problem in the 
1980s, a whole batch was scrapped from... let's say, a European research 
facility. Naturally, a ham friend took one home.

This was about a 2.5kW size, significantly bigger and heavier than the 
600W on in Pat's picture. It had a vent plug that was intended to be 
secured for storage or transit, and then loosened when in use. 
Naturally, a film of PCB oil had crept out all around the plug.

Unfortunately there is no way to know the history of this. These loads 
could have been filled with PCB at the Bird factory; or they could have 
been shipped to Europe dry. In the latter case, there is no way to tell 
if the PCB was used either with Bird's knowledge, on Bird's 
instructions, or totally on the customer's own initiative. All I can say 
is, it can happen.

The smell is not strong but it's distinctly 'chemical', quite different 
from mineral oil. There are other more complex ways to test this, but 
the smell alone should be enough. (Whoops, just noticed John's message 
that Diala mineral oil could also be mistaken for PCB.)

Agreed that PCBs are not acutely dangerous to the user unless strongly 
heated (don't smoke) or ingested. Occasional minor encounters are not 
likely to be harmful.


-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
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