Talk:Current transformer

Regarding Current Transformer

is va rating of changes when its primary changes —Preceding unsigned comment added by 203.124.22.196 (talk) 13:13, 1 July 2009 (UTC)

Where should we use Dead Tank & Live Tank CT's?

Where the drawings show them to be installed. An encyclopedia is not a how-to manual. --Wtshymanski (talk) 14:41, 29 September 2008 (UTC)

Jargon? I don't see a lot of jargon here. Jargon is a shorthand like slang among users. the terminology used here is recognized by published standards and understandable to the trained group that applies these devices. It may be esoteric to the public but technically correct. —Preceding unsigned comment added by 141.197.8.183 (talk) 19:03, 8 January 2009 (UTC)

Yeah, but...this is a general purpose encyclopedia, not a tutorial for EE students. The discussion should be a lot more general. Well before we start talking about the differences between IEC and Australian standards, we should *show* a couple of loops of wire around an iron core! Describe the forest first, then talk about the spores on the moss on the bark of one of the trees. --Wtshymanski (talk) 16:09, 27 January 2009 (UTC)

2.if the primary conductor is not placed at the centre , why there will be inaccuracy, will someone please explain me? and will it be applicable for rectangular type current transformer? —Preceding unsigned comment added by Swadesh20002105 (talk • contribs) 03:13, 12 February 2009 (UTC)

pleas can someone look to my last changes into Current transformer Article, and correct it because my english is not very good.--Noinrush (talk) 17:47, 14 February 2009 (UTC)

This sentence used the word 'primary'. I changed it to 'monitored'. "A current transformer also isolates the measuring instruments from what may be very high voltage in the 'primary' circuit." "A current transformer also isolates the measuring instruments from what may be very high voltage in the 'monitored' circuit." The word 'primary' refers to the primary winding of a transformer. The word 'monitored' refers to the circuit under test or being measured. --Sponsion (talk) 08:49, 17 October 2009 (UTC)

current transformer grounding

I saw a main switch board whose current transformers secondary in grounded. Can anyone tell y it done. Pls mail to my id saaj_an@rediffmail.com —Preceding unsigned comment added by 112.110.201.230 (talk) 17:54, 8 February 2010 (UTC)

SELECTION OF CURRENT TRANSFORMER

I have one simple question ,

My cable current carrying capacity is 40A And My breaker size is 125A , can any one pls suggest CT rating which i want to select? please justify ur answer and send your answer to indra215@gmail.com —Preceding unsigned comment added by 122.166.51.37 (talk) 10:01, 27 September 2010 (UTC)

Burden

The article introduces this alternative term for the 'load' of a current transformer without giving the slightest clue as to why it is used. I included this information in the section on 'burden'. User:Wtshymanski decided that its inclusion was "excessive" and reverted the edit. This is supposed to be an encyclopedia for christ's sake. If a different term from that normally encountered is introduced in an article, there must be an explanation of why it is used. 109.145.21.107 (talk) 17:34, 24 February 2012 (UTC)

Appeals to legendary figures aside, the two words are synonyms. Saying "actually" in an encyclopedia article is pompous at best. --Wtshymanski (talk) 18:44, 24 February 2012 (UTC)

Synonyms they may be but "burden" is, to my knowledge, never used in a context other than instrument transformers. A less knowledgeable reader my wonder why the word "load" is not used. 212.183.128.154 (talk) 18:55, 24 February 2012 (UTC)

how current transformer works

There is no description on what principal current transformer works...lot of physics behind CT is missing. — Preceding unsigned comment added by 210.212.58.111 (talk) 20:16, 24 November 2012 (UTC)

Focus on high power applications

At the moment this Wikipedia article is rather unbalanced, especially the introduction, and focuses on the electrical power supply industry, but current transformers have many uses, from low power, low voltage to very high power, very high voltage. In the same vein, an image of a low power CT would benefit the article. CPES (talk) 10:53, 13 October 2015 (UTC)

Edit Notes

Added information about referring the secondary impedance to the primary, as part of an electrical engineering class project. CatAtDusk (talk) 22:58, 8 December 2015 (UTC)

Function: Distinction between voltage transformer and current transformer

I think that the second line in the function section could use a little reworking. It says “In principle, the only difference between a current transformer and a voltage transformer (normal type) is that the former is fed with a 'constant' current while the latter is fed with a 'constant' voltage,“ which is not actually true. Current transformers are typically not driven by constant current sources. The principal distinction is the impedance of the intended secondary load. A current transformer is designed for a low impedance load such as an ammeter or short circuit and in fact, may be damaged by a high impedance load or open circuit. A voltage transformer is designed for a high impedance load like a voltmeter or open circuit and may, in fact, be damaged by a low impedance load or short circuit.Constant314 (talk) 21:44, 18 September 2016 (UTC)

It's talking about the primary circuit not the burden; the primary has to substantially act as a constant current source for the current transformer; and the supply to the primary has to be substantially a constant voltage source for the voltage transformer behaviour. Indeed, if you think about it carefully, if you apply a constant voltage source to a current transformer, it blows up, because you applied the constant voltage source, and vice versa.GliderMaven (talk) 22:17, 18 September 2016 (UTC)

I'm not buying current source, but I agree that when using for its designed purpose, the impedance looking into the primary (with the proper secondary load) is much less that the impedance of the circuit it is inserted into. As an aside, I have used these backward, in the lab, by connected the secondary to a Variac and putting a large diameter (2 cm) conductor short circuited through the primary hole to generate large AC currents.Constant314 (talk) 16:37, 19 September 2016 (UTC)

Current transformers are analysed using circuit theory in scenarios where the primary is connected to a current source; and your description of "when using for its designed purpose, the impedance looking into the primary (with the proper secondary load) is much less that the impedance of the circuit it is inserted into" is functionally equivalent to that.GliderMaven (talk) 20:18, 19 September 2016 (UTC)

I think when the choice is between describing how they are really used and describing a functionally equivalent use that the former would be preferred. The power transmission line just isn't a constant current source. Its impedance and current is constantly changing. But, I'm going to leave it for a few days and then maybe have some suggested language. Constant314 (talk) 23:38, 21 September 2016 (UTC)

Function... "constant current"?

"the former is fed with a 'constant' current while the latter is fed with a 'constant' voltage, where 'constant' has the strict circuit theory meaning"

What is this trying to say? What is the supposed "strict circuit theory meaning"? How does "constant current" apply here, given it's discussing AC, which is not constant by definition. Gwideman (talk) 16:25, 27 May 2019 (UTC)

It could be worded better. It means that from the point of view of the current transformer, the rest of the primary circuit can be considered a constant current. In other words, the presence of the current transformer should not significantly change the current in the circuit being measured. More precisely, the impedance presented by the current transformer primary to the circuit being measured must be low with respect to the impedance of the circuit being measured. Constant314 (talk) 16:47, 27 May 2019 (UTC)