Misplaced Pages

Revision as of 16:20, 30 April 2014

This is my second edit, and so far things appear to be fine. I was warned by friends to stay clear of Misplaced Pages, due to hostility from established users and from Administrators watching every edit to for 'vandalism' as they call it. Luuluu MuuMuu (talk) 11:05, 10 March 2014 (UTC)

March 2014

Hello, I'm Skr15081997. I wanted to let you know that I undid one or more of your recent contributions to Railroad electrification in the United States because it did not appear constructive. If you would like to experiment, please use the sandbox. If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page. Skr15081997 (talk) 09:38, 28 March 2014 (UTC)

Talkback

Skr15081997 (talk) 16:22, 28 March 2014 (UTC)

I am finished with Misplaced Pages!

As per my second edit, I was warned by friends to stay clear of Misplaced Pages, due to hostility from established users and from Administrators watching every edit to for 'vandalism' as they call it.

It took just five edits before the heavy fist came downn. I did what I was supposed to ... read about the policies, and the five pillars.

Where did it get me --> NOWHERE!!

I should have heeded the warnings. - Luuluu MuuMuu (talk) 16:57, 28 March 2014 (UTC)

I think your 'friends' have exagerated somewhat. The admins are not watching every edit for vandalism. They rely on reports from other users for that, and even they only get excited when there is persistent vandalism. I note that you were critisised above for what seems to me a perfectly reasonable edit, though you had removed a 'needed tag'. Was this because you changed the meaning of the sentence and thought that the bit you removed was being challenged? Anyway, I note that no one has restored the tag.

I also grant that there are a few problem editors about, but that is inevitable in a project this size, but I will let you find then on your own! –LiveRail < Talk > 17:24, 28 April 2014 (UTC)

Original research and synthesis

Thank you for your interest in Railway electrification system. I note that you are a relatively new editor to Misplaced Pages, but you already seem to have a grasp of many of its policies (or is this a fresh start account?). You were, of course, perfectly entitled to challenge my addition to that article as it was, at the first insertion, unsourced. Misplaced Pages etiquette normally requires a claim that you are challenging to be flagged with a tag (unless the claim is patent nonsense). I note that someone did precisely that. If the required reference is not forcoming after a reasonable period, then the claim can be deleted with impunity, though a prefereable strategy is to find and provide a suitable reference yourself.

As for your claim of original research, this is not the case here.

Real original research, is if I grabbed a length of rail and measured it's resistance for DC and AC, and used those results to support the claim in the article. This is strictly not allowed. Though I could use someone else measuring said resistances if they were published with an authoritative backing.

The problem you complained of is a variation of original research called synthesis where one or more references are 'interpreted' to advance a position not directly covered by those references.

But that is not the case here. The statement, "... the dimensions of of a third rail are physically very large compared with the skin depth that the AC current penetrates ...", is directly supported by the supplied reference because it supports the current depth of AC at around 0.3 mm in steel. No conductor rail (or any rail) is anywhere close to approaching that small size. This then supports the claim that,"This effect makes the resistance per unit length unacceptably high compared with the use of DC", because the skin depth area is less than one hundredth of the rail cross section area (this can be established through established geometrical calculations - which are easily citeable from any half decent book on geometry). Resistance per unit length is inversely proportional to cross section area (a well established and easily citeble phenomenon - see next para, though I note it's not cited at Electrical resistance where it seems to have been accepted as it is well established princple). "The use of AC is not feasible because ...", is a direct and obvious logical conclusion. It is no coincidence there is no AC three rail system anywhere in the world. To use AC, you have to go to overhead wire high voltage distribution where the cross section of the contact wire is smaller than the skin depth of copper (around 10 mm or so).

Not everything has to be precisely cited on Misplaced Pages (see WP:BLUE). Statements that are generally acceptable by concensus can stand uncited as long as they are citeable (that's policy though some believe that even citeable is unnecessary). I note that two other users seem to be perfectly happy with the claims and the citation used to support it. One has even pointed out that this is a well understood phenomenon, which is why there is no shortage of citeable material to support it - but then following a claim with a few hundred references is just overguilding the lilly. –LiveRail < Talk > 17:04, 28 April 2014 (UTC)

Thank you for you kind message.

Unfortunately I have read your analysis on the talk page, and I see many flaws in your "analysis". Prepare yourself for some serious feedback. -Luuluu MuuMuu (talk) 23:44, 28 April 2014 (UTC)

Please confine the discussion to the talk page where it started. You are on my watchlist so I will be alerted to any response that you make.

Please take the time to read WP:HOUND ... it could save you from being blocked from editing.

If you believe there are flaws, then you are effectively saying that you believe an AC three rail system to be possible. Since my referenced claim seems to have been accepted by others, I await your evidence that AC three systems are practical with considerable interest. My employer and every other builder of 'metro' light rail systems may also be very interested because they all currently believe it to be impractical (even with non ferrous rails). It is, of course, quite possible but only if the substations are ridiculously close together (<20 metres). –LiveRail < Talk > 10:55, 29 April 2014 (UTC)

Your reaction reveals to me that you feel insecure in your position. The fact that a few other Wikipedians agree with you does not make you correct. As for your employer, if they are looking at this page, then if I were you, I would be worrying about my professional reputation. What is flawed about your argument is the skin depth, and how it affects the flow of AC current. But lets not get ahead of ourselves, this discussion needs time to brew.Luuluu MuuMuu (talk) 17:28, 29 April 2014 (UTC)

It is clear from your comments above that you clearly do not understand the subject that you are attempting to discuss. What effect do you think that skin effect has and why do you think electrical engineers consider it important? If you are not conversant with a subject, it would be better for the project if you did not attempt to contribute to those areas but stick to what you do know.

Skin effect is a complicated subject and I will attempt to put it as simply as possible (and let's stick to our conductor rail). A DC current is distributed throughout the entire cross section of the rail. An AC current at 50 Hz flows only very near the surface of a steel rail. There is a maximum wall thickness of a tube of exterior dimensions equal to the solid rail where the resistance to DC current is practically the same per unit length as to the AC current of the specified frequency. As the wall thickness is made smaller, the resistance to AC and DC increases more or less together. However, as the wall thickness increases, the resistance to DC falls with the inverse of the increasing cross sectional area. However, because the AC current does not migrate much beyond the skin depth, the decrease of resistance to AC becomes less and less as the wall thickness increases (and the cross sectional area increases). The skin depth that calculations using the resistivity and relative permeability of the conducting material give you (and tables and graphs depict) represents the depth at which the current density has fallen to 1/e of the current density at the surface (about 0.37). This figure conveniently gives the wall thickness of the tube that has the same resistance to AC as the solid conductor would at the same frequency (to be pedantic: not exactly but the error is negligible).

The skin depth for steel is less than 0.3 mm (exact value depends on the composition of the steel - but let's stick with that figure). This means that for 50 Hz AC operation, the solid rail can, at least electrically, be replaced with a tubular rail with a wall thickness of 0.3 mm and it will have the same resistance as the solid rail. My calculator tells me that the AC resistance of the tube (and hence the solid rail) is a little more than 150 times greater than the DC resistance of the solid rail. DieSwartzPunkt (talk) 15:13, 30 April 2014 (UTC)

It would appear that it is your position that is insecure as you have to resort to insulting comments. As far as I am aware, I have treated your comments and views with the respect that they deserve. If you are not prepared to do likewise then expect an editing block, or at the very least a refusal to discuss the subject further.

That said: I am inclined to DieSwartzPunkts's view that you are not fully cognizant of the subject. Read what he has said, it is a reasonable description of the problem. A fuller discussion can be found in the article at Skin effect. For your and DieSwartzPunkts's information, the grade of steel currently used on UK railways has a skin depth of 0.16 millimetres. This applies to both the conductor rail and the return running rail.

There is another good example of the skin effect often clearly visible. Next time you are out for a walk in the country, have a look up at overhead electrical pylons. Some of the larger ones are strung with multiple cables for each phase. Now: why would that be? Clue: it is not for the aesthetic appearance. It is because the skin effect limits a copper conductor to about 0.66 inches (17 mm) at 50 Hz. Any larger and the resistance does not significantly decrease (and hence current carrying capability does not increase). Further the wires have to be supported such as to be apart from each other otherwise one cable will affect the resistance of its neighbour. –LiveRail < Talk > 16:20, 30 April 2014 (UTC)