Talk:Shunt (electrical)

hi, is this thing on? I am trying to come to terms with the shunt(electrical) page and would like add my own spin on the thing. Mostly just clarification with a slightly different approach to the explanation itself. once I get the hang of this place I will be right back, need to get advice. Thx1138samos3 (talk) 04:24, 9 January 2013 (UTC)

Measurements using current shunts

Anyone with experience using current shunts knows that their application to an inappropriate instrument can lead to disaster. I submit This Application Note for inclusion in the External Links section of this article to advance user awareness in this crucial but little understood area. Who knows, it could even save a life. I'm the author of the piece, which apparently disqualifies me from linking to it myself (as unenforceable a rule as that might be). Regardless, anyone contemplating measurements using a current shunt should read this information first.

Finally, this Note was previously linked and subsequently removed as spam. If such is the conclusion after this attempt, I'd like an explanation. Rwl10267 19:22, 26 April 2007 (UTC)

Note that User:Rwl10267 is a Dataq Instruments employee and we've been having a problem with dataq.com external link spam. See User_talk:Requestion/Archive_1#Is_Spam_ANY_link_to_an_external_site.3F.3F for details. I recommend not adding the dataq.com link. Thank you. (Requestion 20:13, 26 April 2007 (UTC)

I suggest that the value of the external links be evaluated on their merit as opposed to a snap judgement and prejudice on the part of Requestion. Do the links, and the one on this topic specifically, further the efficacy of the article -- yes or no? As a sidebar DATAQ Instruments puts much talent and effort into advancing the understanding and overall education of electrical measurement instrumentation for our customers in a non-commercial sense, and we have edited article content (beyond mere external links) whenever appropriate. The links branded by Requestion as spam have survived many such reviews by other other editors. As such, his comment that "we've had a problem with dataq.com" should be translated to "I've had a problem...".Rwl10267 21:02, 26 April 2007 (UTC)

Not true. A different editor had to delete [1] your dataq.com spam and warn you [2] back 2004. That is just one example. (Requestion 21:52, 26 April 2007 (UTC))

Guilty as charged...three years ago before I understood the rules. Can you find a recent example, or am I scarred for life? Better yet, I'll ask you this question for the third time with the fervent hope that you will not again refuse to answer: What is it about This Application Note that constitutes spam? Treat it as an education process for me. I'd really like to know, and I mean that honestly. Rwl10267 13:43, 27 April 2007 (UTC)

OK, here are some recent examples of other editors removing dataq.com linkspam [3] [4] [5] [6]. Let me quote two of the summaries: "revert to remove non-relevant commercial link" and "rm link to unreliable article." For why your link constitues spam see the WP:COI guideline which says to avoid "linking to the Wikipedia article or website of your organization in other articles (see Wikipedia:Spam)." Please also see WP:EL#Advertising_and_conflicts_of_interest. Your incredible persistence with adding dataq.com links clearly shows your conflict of interest. (Requestion 19:16, 27 April 2007 (UTC))

Yes, but you have to admit that I've gotten so much better. The ones you cut survived for months and several spam sweeps before meeting your mighty sword. Tell you what, I've got better things to do than debate this matter with you, and I'm sure you with me. What if I fold the content of This Application Noteinto the article. I'd edit it somewhat, but not to remove commercial content, since that doesn't exist. This effort would be time-consuming compared to a simple link, but at least the content would be included. Do me a favor? Review the link for improprieties and let me know if it's suitable largely as-is. I don't want to go through this effort only to have the article revert to a previous version because of another breech in protocol. Thanks. Rwl10267 12:49, 30 April 2007 (UTC)

Yes I admit, you have gotten much better. :) I'm a spam fighter and I'll be happy as long as I don't see that dataq.com external link any more. It would be fine with me if you added parts of your application note to this article but I would recommend a complete re-wording and re-structuring. Just like I'm a spam fighter, there are many Wikipedians who specialize in copyright violations. So if you just copy and paste chunks of your app note they will be quickly detected and deleted. It is also best to avoid mentioning any specific products, keep it as generic as possible, this is an encyclopedia after all. (Requestion 19:20, 30 April 2007 (UTC))

Thanks for your guidance. Rwl10267 12:21, 1 May 2007 (UTC)

Inductive shunt

Add a section/page detailing an inductive shunt found in a transformer 07:07, 31 July 2007 User:65.80.180.219

Ya gotta love it

Mere months after this battle with Requestion, the application note in question has been linked by a completely independent source for the Isolation amplifier article. Spam, it seems, is in the eye of the beholder. Rwl10267 (talk) 15:18, 18 March 2008 (UTC)

Accuracy

The article says "Common Accuracy is +/- 0.1%, 0.25% in North America and 0.5% in the rest of the World." Why should the accuracy be better in North America than in the rest of the World? —Preceding unsigned comment added by 141.51.111.147 (talk) 08:47, 15 May 2009 (UTC)

Answer

Take a look at manufactures, Empro, CSI, Ram Meter and Deltec in North America, then compare to manufactures in the Europe Crompton, Thermovolt, and Isabellenhuette. The china manufactures are to numerous to list. This is the stated spec difference what is standard from North America manufactures vs the rest of world, its there for the reading if you care to check.

Take note the stated accuracy should be tested at room temperature 20C to 25C 68F to 77F with current setting not to induce self heating. Please also note accuracy does not take into account thermal drift differences in shunt designs nor in the Manganin alloys available. The design can affect thermal drift error so much it can make 0.5% accuracy look small in comparison.

to be upfront and honest i work for one of the manufactures —Preceding unsigned comment added by 99.38.56.100 (talk) 06:50, 9 June 2009 (UTC)

Well that hasn't exactly answered the question, you are just confirming that the article is right. The question was what is the reason for the difference in specs? Making anything to a higher spec than needed usually involves higher than needed costs. So the presumption is that US users have a need for the higher spec for a reason, as yet, not established. It would be good to have this in the article if sources can be found. SpinningSpark 12:49, 9 June 2009 (UTC)

American manufactures normally recommend that shunts "not used at more than 2/3 of the rated current under normal operation conditions", to quote one such company. However, I believe that euro practice is to rate shunt for full current. This may have some effect on accuracy? Suckindiesel (talk) 16:08, 9 June 2009 (UTC)

Thermovolt started making this statement about 8-9 years ago in short its a lie. I believe the quote was 100% duty cycle vs Empro and CSI 66% duty cycle. Thermovolt got away with this because of the use of Silver solders as most of the world does also. Silver solder is a far better alloy to use for numerous reason mechanical strength, electrical properties, and you can push the shunt to 100% duty cycle without melting the shunt in half. But the manganin alloy can not survive that abuse after 140C the set resistance is destroyed as the alloy has been annealed. The US manufactures use soft solder alloys because its cheaper and shunts A. should never see temperatures above 120C B. should never be loaded where silver solder strength is required. Putting mechanical stress onto manganin again will drift the resistance. Another common application for manganin is in scales do to resistance changing linear to pressure. Also note Soft 50-50 tin-pb solders normal plastic range is 180C to 190C ROHS solders are 200C to 220C. Thermvolt has backed of these statements a couple of years ago.

I know of one company it cost them over million dollars believing 100% duty cycle. Another company I redesigned a shunt so it at least not get above 110C. The company has had to issue a recall. The point of a shunt vs Hall or CT is no adjustments for thermal drift, better accuracy and be cheaper. Running a shunt 100% duty cycle in the same footprint of shunt from North American design rated at 66% is comical. Don't forget Watts=I^2R —Preceding unsigned comment added by 99.38.56.100 (talk) 15:07, 10 June 2009 (UTC)

Answer: The reason dates back an outdated IEEE spec from the 1930's and 1950's, and when Weston, Westinghouse, GE manufactured shunts in the US. The push back then was higher quality and cost was not a concern. So it just became the norm. Is the accuracy needed, No for most applications. Yet in Europe do to design limitation on some common designs getting the resistance to read in repeated to >.5% test is near impossible. So it became the norm for the rest of the world.

Its kinda of like why the North America is 60hz and the rest of the world is 50hz. Answer Some idiot in Europe 100 years ago decided to do that why for really stupid reasons.

Another Example is why is the North America common output 50 and 100mv and rest of the world is 60 70 and 150mv. Because someone 100 plus years ago decided to do it that way. Can i give a technical reason with really good guesses into a persons thinking Yes but i have no ability to cite sources

Cost difference between .1% to .5% is unnoticeable with today's manufacturing methods. The cost difference is jumping to .01% this is normally 50 to 100X cost increase.

Shunts are very obscure today with very few engineers having a detail understanding of the mechanics/physics involved and even fewer that have access to formulas used to design shunts. Are there sources to cite yes, yet None that would not be removed due being spam. I have research dating back to the 1950's to my own current research.

What happened to all the research on shunts. Tensely in the UK lost all their research in a fire back in the 1960 or 1970's not sure of the date. NIST has just lost theirs, yet we do have notes on the Coaxial Shunt and Thomas type shunts. Leeds and Northrup research was destroyed by Honeywell in the 1990's after the buy out and sequential shut down. Empro purchased all the research from Weston and Westinghouse. Crompton does more with meters than shunts so its a dry well. Isabellenhuette not sure what's happened to their research, it obvious reading the technical information with so many conflicting notes the technical skill is gone from that company. Wilbur Driver Harris one of the Manganin produces from 100 years ago went bankrupt in 1999 so that research is gone. All the other manufactures are relatively new comers and purely copy the companies that been in the industry for ever.

Measurement International and Guildline both have a great deal of research in resistance and current measurement methods but they don't share or publish anything.

So best of luck finding sources. 16:22, 9 June 2009 User:99.38.56.100

Possible incorrect statement

In Applications, Defective device bypass, there seems to be something wrong in the statement that higher electrical resistance "creates" additional voltage.

QUOTE << When the filament burns out in one of the incandescent light bulbs, the electrical resistance becomes very high. The much higher voltage that this creates (equal to the full line voltage rather than the normal voltage divider level) >> END QUOTE

69.196.178.162 (talk) 04:33, 7 September 2009 (UTC)

No, the statement is correct, but perhaps its meaning is unclear. In the example given, Christmas tree lamps, the lamps are wired in series. E.g. say 22 lamps supplied at 220 V, each lamp "sees" 220/22 = 10V. However, the full 220 V appears across the burned-out lamp, causing the shunt to short out and re-storing the circuit. The voltage across the remaining 21 is now higher than before, i.e. 220/21 = 10.5 V. Suckindiesel (talk) 11:06, 7 September 2009 (UTC)

Possible incorrect statement

QUOTE << In this case the shunt, a manganin resistor of accurately known resistance, is placed in parallel with the load so that all of the current to be measured will flow through it. >> END QUOTE

That doesn't make sense to me. I changed it to "in serie". Anon

Doesn't make sense to me either, I see it's been changed back to "parallel" again, which is incorrect Suckindiesel (talk) 12:42, 25 April 2015 (UTC)

Use in current measuring

Does anybody other than me feel that the three figures in this chapter are, at least at first look, rather misleaing?

On any first look the resistors in the diagrams look like the point is to show them as being connected in series with the load, when they are indeed meant to be understood as being shunted (in parallel) with the meter.

Should there be made new figures, or should one just add some explicit description of this in the text? –Øyvind Teig (talk) 12:23, 23 April 2020 (UTC)

Update: I did make a new figure and showed it in an introducory chapter Shunting an instrument but series connected in circuit. I assume that's better than fiddling around in the "Use in current measuring" chapter. --Øyvind Teig (talk) 09:33, 24 April 2020 (UTC)