Little Cook/AG2

This coil was commissioned by Glasgow Caledonian University as an exciting gimmick to deploy at conferences, trade fairs and the like. Its first assignment was the UK Innovation exhibition in Shanghai. I was sent to operate it for a fortnight, and it coped with the 32 degree heat and humidity better than I did. It has since been converted to 120V and sent to the USA.

“Little Cook” was the working title, however it ended up named AG2 for secret reasons. 🙂

The unusual thing about this coil is that it comes complete with its own Faraday cage, made from a 19″ rack flightcase. This allows it to be used in public venues with no special safety precautions. (My boss’s idea, not mine 🙂 )

The resonator is made of laser-cut acrylic sheet and acrylic tube, wound with 0.125mm wire and operates at about 220kHz. It was designed using FANTC/JavaTC and worked first time with no tuning required.

The drive circuitry is contained in a 19″ rack chassis at the base. It is a half-size copy of Mjollnir: a half-bridge of miniblock IGBTs controlled by one of my Mk2 PLL driver boards. The primary tank capacitor is also housed in this chassis: 5 strings of 7 68nF, 1600V film/foil caps. A large centrifugal blower keeps everything cool, and there is a thermal cutout on the IGBT heatsink in case it doesn’t.