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)
It's been five months, and MITERS' facebook page lies latent. This is more than just another good cause. This is an Engineer's cause. This is a human cause. This is a MITERS alum, halfway around the globe, calling for backup!
VIT girls could really use some MIT power. I know it may sound absurd, but at this moment in history, a few MIT students can make a HUGE difference simply by sharing this on their fb timelines.
Stop Gender Discrimination In VIT WHAT IT MEANS TO BE A WOMAN AT VIT UNIVERSITY – GENDER DISCRIMINATION CONTINUES! I am a woman studying at VIT University. Since I was born with a vagina instead of a penis, I must be subjected to humiliating discrimination at the hands of India’s ” best” private engineering institution. I am being jailed inside the campus during exams. I can’t even go across the street to buy fruits. There are no such trumped up rules for guys. They are treated like adults. But women are treated like scummy dim-witted fools who can’t be trusted. I am not a girl, but a woman. The reason they have bothered to give us is that it is exams and we should be studying. Why is it only the girls who need to be studying? Why aren’t guys being confined inside the campus too if the actual reason is studying. Are girls just plain dumb. I score more than most guys in my class. But no, it is me who needs to be jailed so that I can study. I am not a girl, but a woman. Most of the drug and alcohol problems in the campus are because of the guys, but it is only the girls who are subjected to humiliating rules. Why? Isn’t it because they know that they can’t control guys like they can control girls? Isn’t it because girls are more mellow and willing to listen? Yes, we are indeed being rewarded for being good. I am not a girl, but a woman. Don’t they realize that women will one day overcome the fear which rules this place and speak out for themselves. Even Hitler’s dictatorship was challenged by those who he ruled. And they had to pay a much higher price than suspension or expulsion from University. Understand this now, and understand it well. My honor and modesty is none of anybody’s damned business. I am not a girl, but a woman. We were promised in January that our voices will be heard. They promised they won’t do this again. And yet here we are, back to square one. Should we still have faith in what they promise us? Increasing the weekend curfew time from six to eight is not enough to buy our souls and freedom. I risk a lot when I try to speak against this. But it is unbearable. My blood boils when I see my fellow students being subjected to this kind of discrimination. And they are being forced to keep quiet because, hey, they can expel us and ruin our careers if we don’t act like cattle and speak up for ourselves. Self Respect is too great a price to pay for a career. I am not a girl, but a woman. I request anyone who believes in gender equality to share this article and spread awareness. People need to learn to stand up for what they believe in. We are not girls, but women.
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: