Lab work

As you already know, I am working on a thesis concerning self-blast circuit-breakers.

Hopefully, the lab-and-testing part of the thesis now lies behind me. I have acquired quite a lot of data and what I have to do now is to find out what this data can tell us about the processes in a self-blast circuit-breaker at current zero.

After the mobile phone disaster the rest of the testing went quite well.  The last part was a bit more strenuous because I changed the insulation gas from CO2 to SF6. SF6 is a gas with very good insulation properties but also a greenhouse gas (22000 times the global warming potential of CO2) and the chemical byproducts produced when it is exposed to arcs are somewhat unhealthy. Therefore it needs to be handled with care. For the climatic part there is a filter and a tank so the gas can be reused several times. For the health part, we use this:

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Looks good, isn’t it?

It’s rather cool to work with dangerous stuff. Makes work more thrilling. And it kind of compensates for the uncoolness of a lab in the basement which nobody (except the people who need and use it) ever enters.

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And my mobile phone went BOOOM

For my thesis I’m working in the lab in the Institute for High Voltage Engineering where I am researching on a self-blast circuit-breaker, trying to measure the voltage drop within the arc during switching.

A self-blast circuit-breaker needs a pressurized insulating gas to quench the arc. Therefore the CB that we use is installed in a vessel. From the vessel the air is evacuated and then it is filled with insulating gas – either SF6 or CO2. Because it is very dark in this vessel, I switched the light of my mobile on and put it inside the vessel, connected the breaker, checked the connections, checked again and then closed the vessel.

Well, the phone was still inside. I evacuated (10 mbar), put in the CO2 (4 bar) loaded the test circuit and gave the breaker some 5 kAmps (peak).

Measurement went well, data is safely stored, labmate comes in talking on his mobile, I think, hang on, where’ s my mobile? and the thruth dawns on me…I rush inside the lab (not forgetting to check for safety) open the vessel and … there it is, the light still on.

Good lord, I thank thee for salvaging the stupid ass’s mobile. And I never ever again want to feel like I felt in the moment I realized what I had done…