I managed to successfully carry out the coilgun demonstration without any casualities at MAS. Although my diodes were extremely under-rated (read the rest of this post for further info), they survived the charging until 400v. But the firing at 400v was disappointing. The nail only managed to make a small hole at the can. Should have done a 960v test fire. But I am sure there will be a spectacular explosion before I manage to charge them up.
The overall coilgun setup.
I started my presentation by letting the class listen to a sound clip of a can being shot by my coilgun a few years ago. You just hear “bang” followed by the rattling of the can. Then I asked them if they wanted to know what made that sound. Who would say no?
My beloved SCR. Handles everything you throw at it.
I gave a short powerpoint presentation on how a coilgun works. After all the main parts of the gun was explained, I proceed to do a live fire.
My canisters of death. Rated at 960volts and 3440uF.
Since I was in class and firing at full power with defective diodes wasn’t logical, I only fired at 400volts. For me, it was very disappointing. For the rest of my coursemates, they were clearly impressed. They were still talking about it today and I’m now known as the class terrorist.
The exploded diode.
Anyways, a diode exploded right in front of me the other day. The sound was so loud that I got ringing in my ears after the explosion. I was saved by the pmr sejarah paper that I put over the diodes. I only went temporary deaf. The same couldn’t be said about the sejarah paper.
So be careful out there. With high powered stuff, you’ll never know when your time is up. So I’m going to Pudu tomorrow to get some 1200v 20amp ultra fast recovery diodes. That will take care of the exploding diode issue.
Silver bullets. Continue reading