With the semester almost ending, I’m glad that my second DRSS-Tesla Coil is finally done! DRSSTC 2 began almost a year ago with the goal of making my first tesla coil using brick-style IGBTs.
DRSSTC makes 4 feet of sparks look easy, in MITERS
The project began when I bought two Toshiba IGBT half-bridge modules on ebay, good for 150A 600V. The original plan was to build a compact and powerful DRSSTC running this full bridge, with about a foot long secondary. The coil also uses a revised version of Steve Ward’s UD2 as the driver. After many months of work, I finally got everything put together. Unfortunately, initial tests were worrying, and I soon found out that one of my IGBTs was half-dead. With the lack of time and money, I wasn’t able to continue with these bricks.
I managed to get hold of a CM200DU-24F 200A 1200V IGBT and decided to make a half-bridge coil instead. The CM200 bricks are larger, so I wasn’t able to fit a fullbridge inside the box I had already made. Finally, this worked perfectly and everything came together.
– CM200 Half Bridge
– 208VAC input (2 leads from 3 Phase, though the coil was designed for 240VAC operation)
– 13″ x 3.5″Secondary, ~2000 turns
– 16″ x 4″ Toroid (I want to get a spun one someday)
Introducing my first DRSSTC. It’s a small tesla coil made to be portable and to make lightning at home. This coil is based of the amazing oneTesla pcb. I’m still in the process of doing a detailed write up at http://www.loneoceans.com/labs/drsstc1/!
As a learning experience, I wanted to go for something simple and nothing too fancy. I’ve had the fortune of being in the good company of other brilliant coilers (like Bayley, Tyler, Kramnik), and managed to get an older version of the oneTesla driver PCB, which runs this coil! I faced a couple of problems over the past few weeks but I’ve modified some parts and managed to get the coil working very well! See the video of it in action here:
Important specifications including calcs from JavaTC:
Max spark length – I don’t know yet, does >22″ sparks to free air and ground with ~100us on-time. More testing to come soon. Right now it’s limited by hitting the floor.
222kHz resonant frequency (within 1%)
2.4″ Diameter PVC Secondary, ~2000 turns of AWG36 for a 10.25″ length
3.5″ Diameter Acrylic Primary, 6 turns of AWG 14 for about 0.8″ length
Single 0.101uF 2kVDC 942C CDE Primary Capacitor
340VDC (120VAC rectified and doubled)
Roughly 100us on-time (in the photos here)
2.2″ x 8″ AmazingOne spun toroid
Half Bridge of 60N65 IGBTs (seems to be similar to the 60N60 TO247 IGBTs)
Coupling = 0.22
Energy Transfer time = 9.87us
Performance has been pretty good. Originally, the coil used a 0.068uF 940C capacitor but that made my primary frequency about 19% too high and I lost a 60N60 half bridge. Increasing the primary to 8 turns of 14AWG (k=0.26) turned out to be a bad idea and I had a lot of racing sparks. After a few more coats of Polyurethane on the secondary, a return to 6 turns of AWG14 and a larger tank cap, the coil is in tune with a performance I’m very happy with.
This coil currently has a tiny built-in 19VDC laptop power supply for the electronics which uses the famed UCCs from TI as gate drivers to a GDT driving the gates of the IGBTs. Here’s a pretty photo of the ground ‘lighting’ strikes of the tesla coil:
Lots of people are building Tesla Coils at Miters over the past year, so I was inspired to get my old Tesla Coil 2 out again! It was unfortunately in poor shape and very dusty so I cleaned it up and replaced some parts. I’m now happy to say that Tesla Coil 2 is now back with a new finish and excellent performance!
Photos of the new construction:
And a photo of the coil in action!
Could this possibly still be the biggest homemade Tesla Coil in Singapore?