Friday, April 24, 2009

2400 Volt Can Crusher

The promised and much awaited 2400 volt power supply went through its first test run. The video is up on YouTube. It was a little disappointing it takes 4 firings to get the can into the hourglass shape. One of the capacitors might be bad. Anyway a Microwave Oven Transformer charges six 400 volt capacitors through a 500 ohm 250 watt resistor. The idea is to electronically crush the soda can into an hourglass shape.

The switch to connect the capacitors to the coil is made of two 1/2 inch bolts meeting head to head. They need to be filed off after every 5 to 10 operations as they will melt together if not cleaned up. A piece of plastic holds them apart and is removed by pulling on a string.

There are 6 turns of 10 gage wire wrapped around the soda can. The last time I tried this was at 800 volts and I used about 10 turns of 14 gage wire. The wire was turned into a jumbled mess and every solder connection melted. So this time everything is connected with two 10 gage wires in parallel and fastened together with bolts. The coil has been rewound into 2 layers totaling 5 turns and is now more effective at crushing the soda can.

Below is the updated schematic. The resistors are matched with a volt ohm meter for 10:1 correspondence so that the built in volt meter will read exactly 1/10 of the output voltage. The meter runs on a 9 volt battery, I could have used the filament winding of the MOT but the 9 volt battery was easier.

There are 2 Youtube videos;
Then it was improved with better results;
I have been thinking about the future of can crushing. It is hard to balance this many electrolytic capacitors when they are wired up in series. Some do not completely discharge and some reverse charge. The solution would be to use higher voltage capacitors. One easy source is microwave oven capacitors but they are only 1 uF each. So now I am searching for some capacitors in the range of 10 to 100 uF at 5 to 6 KV. I hope to find something at the Ham fests this summer.

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