High energy capacitive discharge is fairly well trodden ground. See if any of these give you some food for thought. http://www.electricstuff.co.uk/destructotron.html http://www.capturedlightning.com/frames/shrinkergallery.html https://hackaday.com/2012/09/28/how-a-quarter-shrinker-works/ -Denny On Thu, Apr 5, 2018 at 9:01 AM, Van Horn, David < david.vanhorn@backcountryaccess.com> wrote: > > 1. Being able to sustain around 1kV while the contacts are open. > > At least 1kV before the initial contact closure. After that it gets hard > to calculate since there may be residual energy circulating. > > 2. Being able to handle high current on contact closure. > > I'm closing a very low inductance capacitor into a small (10's of uH) > inductance. Current will ramp up FAST. > > 3. Low contact resistance when closed. > > And low voltage drop, though mechanical contacts may be actually worse > than I think in real life. Still lower loss is better. > > > 4. Are not worried about a voltage spec on contacts opening (is the > recharge voltage turned on separately?)? > > Recharge happens as the contacts open, from a different inductor which ha= s > been charging while the contacts were closed. > Current there is <1A, but the inductor is substantial. One of the nasty > things I want to reduce is the losses as the mech contacts open and close > to arcs across the contacts. > The original solution with tungsten contacts work, but the contacts die > (no surprise) > > > -----Original Message----- > From: piclist-bounces@mit.edu On Behalf Of AB, > Pearce - UKRI STFC > Sent: Thursday, April 5, 2018 9:32 AM > To: Microcontroller discussion list - Public. > Subject: RE: [EE] Substitute for mechanical contacts > > Presumably you are really only interested in three things: - > > 1. Being able to sustain around 1kV while the contacts are open. > 2. Being able to handle high current on contact closure. > 3. Low contact resistance when closed. > 4. Are not worried about a voltage spec on contacts opening (is the > recharge voltage turned on separately?)? > > Its ages ago (like back when I was an apprentice) but an RT unit I used t= o > deal with used a relay with contacts about 3/16" diameter (they were > lightly domed) to handle large currents for operating a 75W transmitter o= ff > 12V or 24V. I remember the contacts as being silver plated brass (don't > recall coming across tungsten contacts), and I suspect you are after > something similar. I cannot recall if they would open far enough to take > 1kV in air, but removal of the back contact would allow them to open wide= r. > These were a large (about 2" x 3" footprint open frame relay without a > cover, and I would have thought something similar would suit your purpose= .. > I'm afraid I don't have any info on manufacturer or model, but at the tim= e > I always thought they would be ideal relays to use for switching driving > lights on a car ... > > > > > Is there yet a device that will substitute for real relay contacts in a= n > AC circuit? > > > > I have a test fixture in mind, which is complicated, but the > > interesting part is discharging a low impedance capacitor of about 0.1u= F > at 1kV into a coil, and allowing the current to ring down. > > Spice tells me to expect currents in the kA range, and a prototype > > built with a relay contact seems to confirm this. Tungsten contacts > take a lot of abuse, and they also generate a lot of heat. > > > > Minimal voltage drop, ability to trigger "closure" and "opening" at > > any point in time, huge currents, and bidirectional currents without > turning off are all requirements. > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at http://mailman.mit.edu/ > mailman/listinfo/piclist > > -- > 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 .