Mercury arc valve rectifiers are beautiful

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By Sean Michael Ragan
Posted 2010/05/05 @ 4:47 am
Category Electronics, Science

The thing to have when every other mad scientist on your block is already rocking the Jacob’s ladder. Sure, you have to ignore the fact that it’s loud, clunky, and chock-full of toxic metal, but geez…just look at it. [Thanks, Billy Baque!]

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5 Responses to Mercury arc valve rectifiers are beautiful

Dave on May 5th, 2010 at 8:25 am said:

One quibble – they are indeed beautiful, and I remember the unearthly glow very well – but they are not “arc” devices. The mercury exists as a tenuous vapor, and the tube (“valve”, if you insist!) works on ion flow, rather than electron flow in a normal vacuum tube. If an arc were to form, there would be essentially a dead sort between anode and cathode, and it wouldn’t function very well as a rectifier (diode)…

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Sean Michael Ragan on May 5th, 2010 at 8:42 am said:

Wikipedia calls them “arc valves”:

http://en.wikipedia.org/wiki/Mercury_arc_valve

And I’m not sure I understand the distinction you’re trying to make about what counts as “arc” and what doesn’t. By my understanding, the very definition of an electrical arc involves ion flow: Normally nonconductive media break down, by ionizing, to produce charged particles that permit the flow of charge carriers in a very high EM field.

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Simon on May 5th, 2010 at 12:13 pm said:

The local transport and technology museum (MOTAT) has a tram track that it runs and they use these there. They have several there you can see working (mostly – last time I was there the glass was filthy). You can see the glow change as the trams move up and down the tracks. They definitely call it a mercury arc rectifier.

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robert scott on January 18th, 2012 at 10:18 pm said:

hi all i would like to buy or trade for a working one
email robert.roberts@live.com.au

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Nyanman on January 25th, 2013 at 2:09 am said:

Just found this.
Compared to the older rotary AC/DC converters, Mercury Arc valves are very quiet, very simple, very reliable, very compact, etc.

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