Talk:Mercury-arc valve

message: This article does not explain things quite well enough.  The purpose of the excitation electrode is unclear.  A simple circuit diagram that includes the anodes, cathode, and excitation electrode would be enormously helpful. Benandorsqueaks 05:01, 25 December 2005 (UTC)
replies: text: Whew.  Agreed.  There's whole paragraphs here that are baffling. I'll have a hack or two at cleaning this up - it's worth having this because most of the HVDC project articles refer to mercury arc valves. --Wtshymanski 17:33, 29 Mar 2005 (UTC)
thread_title: Clarity

message: I've got to track down a description of the glass and metal envelope forms, since the article is vague.  I found a picture in "Standard Handbook for Electrical Engineers" which I may try to redraw.  I don't think a thyratron is a mercury-arc device - it doesn't have a pool cathode at any rate.  Triggering is important and not discussed yet. I've *seen* the glass-bulb form but I don't think those have been used since before WWII. A discussion of why solid-state devices replaced the arc valves is in order. Flashback is a problem to be mentioned, as well as cooling requirements.  Mercury valves were developed by GE and Simens as well as ABB - needs references.  --Wtshymanski 
18:09, 29 Mar 2005 (UTC)
replies: text: A thyratron can be either a cold cathode device with a pool of mercury, or a heated (thermionic) cathode device without a pool of mercury. The latter can be either a mercury arc or a mercury discharge device. 20.133.0.13 13:54, 14 March 2007 (UTC)
replies: text: An ignitron uses a pool of mercury, not a thyratron. Thyratrons can use mercury vapor (a small droplet of mercury being the source), but often use other gases such as hydrogen, xenon, deuterium. A thyratron can use either a cold or a heated cathode, but modern thyratrons use heated cathodes exclusively. Bert 14:03, 15 March 2007 (UTC)
thread_title: Notes

message: WHen I click on the picture I uploaded for the article, I can't see it, only it's description page.  What did I do wrong and how do I fix it? --Wtshymanski 03:27, 4 Apr 2005 (UTC)
thread_title: Picture trouble

message: Static inverter stations were used to provide DC power to legacy Edison style DC power grids in urban centers until the 1950's. These were in use in Helsinki until about 1950 and in the UK even longer. Who knows more about this? -- Petri Krohn 06:45, 10 January 2006 (UTC)
replies: text: The UK had a DC link scheme between Kingsnorth power station on the Isle of Grain in Kent and Beddington in South London and Willesden in North London.  There were 3 converter stations and the Kingsnorth station used controlled mercury valves to rectify the generator output into plus and minus 266 kV DC.  The positive pole fed the Beddington station which used identical valves but operating as inverters.  The negative pole similarly fed Willesden.  The scheme also allowed Beddington or Willesden to operate as rectifiers and feed power to the other, but such operation was never required.  The scheme was still operational in the early 1980's, but is no longer in operation. 20.133.0.14 13:52, 14 March 2007 (UTC)
thread_title: Legacy DC power grids

message: Mercury arc valves/rectifiers are still used on the London Underground. They were used for both traction and electric lifs.
This page shows on in use on 27th January 2000 still powering the lift of an air-raid shelter at Belsize Park London Underground Station:
http://www.subbrit.org.uk/rsg/sites/b/belsize_park/index.html
--217.18.21.2 18:31, 9 February 2007 (UTC)
replies: text: There are many examples of mercury arc rectifiers still in operation, mainly in places where the cost of replacement is not considered worthwhile because the use is not intensive enough.  The mercury arc rectifier, generally never wears out. 20.133.0.14 13:52, 14 March 2007 (UTC)
thread_title:  London Underground 

message: The statement about Tungar rectifiers in the "Others" section should be clarified to indicate that these are not based on Mercury vapor, but rather Tungsten (electrodes) and Argon (gas), thus Tung-Ar.
32.97.110.142 18:15, 13 September 2007 (UTC)
replies: text: Noted; moved the description to the rectifier article in with the other electron tube devices. --Wtshymanski 21:07, 13 September 2007 (UTC)
thread_title:  Others 

message: " Before the advent of solid-state devices, mercury arc rectifiers were the most efficient form of conversion from alternating to direct current."
not by a long way. Mechanical rectifiers waste a fraction of the power, and were used in many applications before and after the invention of the mercury rectifier.
62.253.52.61 (talk) 17:47, 9 June 2008 (UTC)
replies: text: Cool. Do you have a reference? Were people still buying rotary converters for DC supplies after mercury arc rectifiers came along? --Wtshymanski (talk) 21:24, 9 June 2008 (UTC)
thread_title: Efficiency

message: McGraw-Hill's Engineering Companion from google books --Stone (talk) 09:44, 5 March 2009 (UTC)
thread_title:  Nice Reference 

message: What properties of mercury are important for the function of  this device? Is the liquid state of mercury not important for operation,  only the electrical conductivity? Can the  device operate lacking the electric arc?--84.232.141.38 (talk) 17:08, 12 April 2011 (UTC)
replies: text: Ionization is the key bit.  A mercury arc valve without an arc isn't operating, but you can have an arc without mercury. --Wtshymanski (talk) 18:09, 12 April 2011 (UTC)
replies: text: How about vapour pressure of mercury? Is it important  for the arc?
If there is arc without mercury, then mercury can be replaced with other metals like NaK, galinstan.--84.232.141.38 (talk) 17:14, 20 April 2011 (UTC)

text: That's original reserach and out of bounds for the article. Have you seen anyone actually using other metals?  Certainly a "mercury free" fluourescent lamp would be a hot seller, but the fact that no-one seems to be offering this indicates it's not the melting point, but the behaviour of mercury on ionization (and the energy of the photons it gives off) that is the key property. --Wtshymanski (talk) 17:58, 20 April 2011 (UTC)
replies: text: How is the ionization expressed by a quantity? If electrical conductivity is the answer (and perhaps ionization energy), then galinstan's conductivity is about three times  greater than mercury's (by comparing data presented in articles). A straighforward comparation is not OR.
On the other hand galinstan is a recent development, but there must be some sources published somewhere refering to the investigation of other metals' appropiateness/suitability for the purpose discuted here. --84.232.141.38 (talk) 18:12, 1 May 2011 (UTC)
thread_title:  Properties of mercury 

message: Did the work of Johann Sahulka precede that of Peter Cooper Hewitt? Biscuittin (talk) 22:06, 2 November 2014 (UTC)
replies: text: Yes -- Sahulka seems to have done that work in 1894, whereas Peter Cooper Hewitt only did so in 1902. 2A02:2C40:100:B001:0:0:1:BC26 (talk) 13:40, 18 April 2024 (UTC)
thread_title:  Johann Sahulka 

message: In three phase, full-wave rectification with 6 anodes, there are multiple ways to wire the anodes.
You could wire them so that the arc always progressed to the adjacent anode (either CW or CCW).
You could wire them so that the arc never progressed to an adjacent node.
Was there any benefit to doing it a certain way?
If the anodes were wired progressively, did CW/CCW interact with the chosen anode arm orientation?
(The one schematic of a 6 anode seems to suggest none of this was considered.)
Temblast (talk) 16:25, 16 January 2016 (UTC)
replies: text: This has the answer for what the sequence is, but it doesn't say why.  I would guess that it is because the further away the next anode is, the harder it is for it to pick up the arc. SpinningSpark 16:50, 16 January 2016 (UTC)
thread_title:  Sequence of anode wiring 

message: At present the article lists one of the methods of striking the arc as involving "magnetostriction" to displace the mercury. Since magnetostriction is an effect present in ferromagnetic materials only and mercury is not ferromagnetic, I don't think this is correct. Rather I think that the author means that the mercury is dispersed by Lorentz forces acting internally in the mercury due to its own magnetic field (from carrying current) and the electrons flowing through the mercury due to the current flow. Sbreheny (talk) 05:39, 3 March 2016 (UTC)
thread_title:  Magnetostriction 

message: Re this "spelling correction".  Both Wiktionary and the OED give buses as a correct plural.  The trolleybus article uses the plural trollybuses.  There may be a difference in UK/US usage here, in which case the issue is within the scope of the WP:ENGVAR guideline. SpinningSpark 18:18, 18 April 2016 (UTC)
replies: text: Agreed. Can't see any source for "trolleybusses" anywhere. Andy Dingley (talk) 18:33, 18 April 2016 (UTC)
thread_title:  plural of trolleybus 

message: Meneuvrier and Jemin are so obscure, they don't even show up on Wikipedia. "History of Electron Tubes" by Sogo Okumura gives a snippet on Google Books which seems relevant, but I don't have the book. Other snippets show up, but they don't seem to figure in the mainstream of mercury rectifier development. But "Cooper Hewitt Mercury" gives thousands of hits on Google Books. --Wtshymanski (talk) 19:25, 24 June 2017 (UTC)
replies: text: I agree with your last edit.  Observing an effect and using that effect to invent a device are two different things. SpinningSpark 08:23, 25 June 2017 (UTC)
replies: text: It would be appropriate to mention them in the history as observing the effect but clearly not altering Hewitt as the inventor imho. MartinezMD (talk) 20:50, 25 June 2017 (UTC)
replies: text: Also relevant is whether Cooper-Hewitt was aware of Meneuvrier and Jemin's work. SpinningSpark 22:12, 25 June 2017 (UTC)
replies: text: For that matter, were Meneuvirer and Jemin aware of Johann Sahulka?  --Wtshymanski (talk) 23:43, 25 June 2017 (UTC)

text: Both names were misspelled. It is fixed now. Pavel Vozenilek (talk) 05:11, 23 May 2023 (UTC)
thread_title: Who?