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Copper showers

I've been playing with the 500A switch on the bench.

It's short-circuit protected. Calculations and simulations are great, but at some point you have to grab something worthy and short the bus bars. Gloves, goggles, and ear plugs are all good.

So, I commanded the SPST switch array closed (shorting the output bar to the GND bar), took a 2 milliohm 0.1F capacitor charged to 25v (to simulate the main power source), cringed, and slammed the cap across the switch's terminals.

Pzzt.

Not bad. Pretty cool.

Disconnected the cap.

BANGGGG!!, struck a blue, half-kA flaming arc, and took a small copper shower. That was thrilling.

Took a nasty nibble from the copper bus bar and blew away half a paper clip. Nothing wrong, nothing electrical damaged, the switch just recovers a bit aggressively from overload--when you remove the fault it recloses before you can get very far away. After repeated trials, the bus bar looks like it offended an insane woodpecker with a titanium beak.

All in all it's pretty neat. The switching precharger works great.

I lost a few FETs and LM393's disconnecting the supply while hot--load dumping it sends a big-volt inductive kick with no supply to absord it, welding g, d, s and zenering the '393. Oops. Fixed that with a TVS.

-- Cheers, James Arthur

Reply to
dagmargoodboat
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Ah! You bring back fond memories of my MHD days ;-) ...Jim Thompson

[On the Road, in New York] 
--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

See? You didn't need help from the like of this group after all!

Congratulations!

Reply to
John S

MHD - a million amps DC at a couple of volts. Interesting but b-hard to harness efficiently.

Reply to
who where

,
a

This group is really a great bunch of guys (and the occasional Sylvia). When we get down to electronics, all sorts of good ideas fly.

I thought the whole SOA discussion was more than worth it.

Thanks guys.

James Arthur

Reply to
dagmargoodboat

It's been many years since I was involved, but it's being used to generate

400kV DC out west. ...Jim Thompson [On the Road, in New York]

-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

formatting link
| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Reply to
Jim Thompson

MHD? Motorola ??? Division?

--James

Reply to
dagmargoodboat

No. MIT Building 20, Professors Woodson and Melcher. ...Jim Thompson

[On the Road, in New York] 
--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

I agree. I forgot the smiley face again.

John S

Reply to
John S

Magnetohydrodynamic. Basically you shoot a plasma jet between two electrodes, with a magnetic field applied at right angles to both. The working fluid is the plasma, so the Carnot efficiency limit is very high.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
Reply to
Phil Hobbs

Were there any little particles of molten, borderline veporous copper skittering across the floor, looking like mini ball lightning?

Thanks, Rich

Reply to
Rich Grise

,

The sky filled, the earth trembled, and the workbench is strewn with 'em.

-- Cheers, James Arthur

Reply to
dagmargoodboat

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