Hi, I need some help here. I am building a gauss gun and need a solid state relay switch because the mechanical switches have such a high power loss. I have it hooked up on a 50volt power supply and am using 3, 50volt 4700 uF capacitors. I also have around 6.5 meters of 14guage .00806 ohms/meter copper magnet wire. If you do the math, with I = V/R, you see that I = 50/.052 = 954 Amps when the capacitors are discharged. I need help in finding an affordable/(CHEAP =)) relay or solid state power switch for my gauss gun.

Thanks for the help,
Ryan

 

Actually, I would expect something less as the capacitor ESR probably exceeds the wire resistance. And the inductance, though small, will prevent instantanious rise of current. Cheap, high current, semiconductors are sort of an oxymoron. One cheap readily available relay (electromechanical) suitable for this service would be a Ford type starter relay. You could actuate this with a small trigger switch and a dropping resistor from your 50 volt supply or from the capacitor bank. Or you might look for some surplus SCRs.

Regards

cww

 

SCR or IGBT

 

Hi Ryan,

Or you could use contactors rated for power factor correction capacitor banks. How frequently are you operating the switches? Is the equipment mobile? How much power is available to trigger the switches.

Solid states do not like high di/dt and high dv/dt. Design could be more involved.

Tomy Zacharia