I forgot to mention that by far the most difficult challenge to this lower-voltage can crusher is to keep the coil intact. The magnetic field produced during the pulse is several tesla in magnitude which causes a hoop stress in the coil of about 1 ton per meter of wire length, for about half a microsecond. On Thu, Jun 11, 2015 at 1:11 AM, Sean Breheny wrote: > Close :) Electromagnetic can crusher. > > I've made several versions and one was very successful but used a > relay switch at 5kV. I've been working on and off for about 2 years on > another variant which uses only 1.2kV and a big bank of electrolytic > caps. In the attached plot, the yellow trace (CH1) is amps at a 1000x > attenuation ratio (1A =3D 1kA). The other trace is the voltage across > the coil. The coil is about 4uH and I apply 1200V across it, the dI/dt > is about 300 Amps per microsecond. This shot had a peak current of > around 33kA but I have had higher. Measuring such current is a > challenge. Current probes or reasonable-sized current transformers > will saturate. Ordinary shunt resistors have too much inductance. I > used a "Current Viewing Resistor" which is a high frequency shunt - > think of it as a large number of tiny resistors in parallel. Each > resistor is already low inductance so in parallel they are even lower. > One CVR I made has on the order of 10pH inductance as seen via the > Kelvin connections. > > This is a photo of the setup: http://tinypic.com/r/24c8pxd/8 > > > On Thu, Jun 11, 2015 at 12:32 AM, John Gardner wrote: >> ...I have a hobby application which switches 40kA... >> >> Rail gun? :) >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .