Power to the People

One of the disadvantages of living out of town is that we get power cuts, especially when there are high winds. We used to get so many that soon after moving here I bought an emergency generator. It has proved a very good buy, I have to run it four or five times a year and it powers the freezer, the fridge and the central heating. It also powers the TV, computers and the lights, but not all at once. Switching on the kettle, the shower or the immersion brings the generator to a sudden, juddering halt.

Having to use it brings home to me how dependent we have become on mains electricity, and how much we actually use. The generator gobbles up petrol and only provides about one-fifth of the peak power we need. Last year, when we had three feet of snow and no electricity, I had it running for five days, during which time it used around eight gallons of petrol (work out the cost yourself – there are 4.5 litres in a gallon).

I am no stranger to generators. Years ago I worked on the test bed of a well known manufacturer of diesel engines. I tested big diesels by connecting each one to a dynamo about the size of a small car. By measuring the output of the dynamo I calculated the power of the engine, its fuel consumption and efficiency. It’s no big deal, it’s done every day by makers of engines. To start everything up there was a large steel switchbox with a handle that I moved from OFF to FULL slowly and gradually. It was old, the kind of switch mad scientists use to energise Frankenstein’s monster. I’d never had trouble with these switches before. They were solidly built, with thick copper bars leading into them (protected by metal guards) and heavy cables leading from them, under the concrete floor to the dynamo.

The morning everything went wrong I was eating a sandwich. The engine, the kind of diesel fitted to tugboats and naval launches, sat ready to run, oiled-up and with its injectors primed. Breakfast sandwich in one hand and switch lever in the other, I eased on the power. The dynamo hummed and turned slowly, turning over the engine that was coupled to it (the engine had no starter motor and this was the way to start it). The engine spluttered, started, and ran quickly up to full speed – time for me to release the switch handle and return it to OFF, except that this time it wouldn’t move, it wouldn’t go forwards or back. About five seconds later, molten copper started to drip from the switch and splash on the floor. The busbars (the heavy copper strips leading into the switch) sagged and melted – and copper melts at 1083ºC. It was awesome. There must have been a lot of smoke because the driver of the overhead crane trundled along to me and threw down a fire extinguisher. It didn’t work. The other two extinguishers I brought to bear on what was now a red-hot switchbox and smouldering surroundings didn’t work either. There were flames, though I’m not sure what from. Burning paint, perhaps. We didn’t manage to find out what caused this little mishap. There wasn’t much left to examine.

I have the greatest respect for electricity, and I have what might be considered by some to be a fetish for fire extinguishers. I have one in my car and about five in my house. There is also one within easy reach of my little generator when it is running.

I wonder why?

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