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Author Topic: Dummy Loads and Transformers PCB Oil Test  (Read 2432 times)
WB2NGX
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Posts: 35




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« on: August 25, 2012, 01:02:14 PM »

A while ago I bought an old Heath dummy load..... full of oil. My main concern was weather the oil in it contained PCB's. Being an  older item I couldn't be sure. Since there is no way to tell by color or oder I decided to research it furthur.
What I found was a couple simple tests that don't require any special equipment or chemicals and any one can do at home.

The first test is for PCB's in the oil, called a density test.
Put a few drops of the oil in question in a glass of water. If the oil floats or sperads out on the top of the water it's free of PCB's. If it sinks then the oil contains PCB's. Since PCB's are heavier than water they will sink. Mineral oil is lighter and will float. However if any are detected this test doesn't tell the concentration amount.

The second test is a chloring presence test. This test checks for chlorine in the oil to determine PCB presence.
This test is done by taking a piece of copper wire, dipping it into the oil and holding the wire over a flame such as a propane torch. Observe the color change of the flame. If the flame strarts to turn green or blue green then PCB's are present. If the flame remains orange none are present.

The oil in my dummy load passed both tests. I changed it anyway because it smelled funny.

I can remember back when car AC systems were leak tested with a propane flame on a special wand. If the flame turned green
you were close to the leak area. I would imagine since refrigerant oils back then contained PCB's the same type of test was used. Later replaced by putting dye in the system and checking with a UV lamp.

So if any one ever wanted to know what might be in that old dummy load you brought back from the ham fest now is you chance to satisfy your curiosity. Please post you findings.

Joe........ WB2NGX
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W0BTU
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« Reply #1 on: August 25, 2012, 06:13:56 PM »

That's interesting. I have a Heath Cantenna plus a 75 ohm Cantenna clone that I made many years ago. Both contain transformer oil. Maybe someday I'll try that test. :-)

If anyone is going to run high power into an oil-cooled dummy load, pay attention to the graph on the side of the Cantenna.
http://www.radiomuseum.org/images/radio/heathkit/cantenna_hn_31_84682.jpg
The short-term power handling capability depends on whether you use mineral oil or transformer oil. Transformer oil has superior heat-transfer capabilities.
« Last Edit: August 25, 2012, 06:18:13 PM by W0BTU » Logged

KB1LKR
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Posts: 1898




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« Reply #2 on: August 26, 2012, 07:09:28 PM »

The green flame from a propane burning refrigerant leak detector arises from the chlorine atoms in the R-12 refrigerant (dichloro-difluoro-methane), not from the compressor oil.

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KE4DRN
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Posts: 3734




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« Reply #3 on: August 27, 2012, 05:27:14 PM »

hi,

PCBs were widely used as dielectric and coolant fluids,
for example in transformers, capacitors, and electric motors.

PCB not used in the compressors for refrigeration.

Chlorine burns green in the flame test, bottle green to be exact.

73 james
« Last Edit: August 27, 2012, 05:44:02 PM by KE4DRN » Logged
WB2NGX
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Posts: 35




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« Reply #4 on: August 27, 2012, 06:49:44 PM »

Yes some older refrigeration appliances made prior to 1979 may contain PCB's.

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KE4DRN
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Posts: 3734




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« Reply #5 on: August 27, 2012, 08:01:13 PM »

Yes, the starting capacitors could have PCB in the oil,
but not for the compressors used for the refrigerant.
Mineral oils for R-12 and R-22 formulations.

73 james
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