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Squabbling about "not tranformers"

Discussion in 'Jokes Archive' started by bernardgreen, 13 Mar 2017.

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  1. bernardgreen

    bernardgreen

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    Remote voltage sensing . Four conductors in the cable. Two carry the power ( high amperage and voltage drop ) to the lamp. The other two, the sensing pair ) return the voltage at the lamp to the control circuit in the power supply, there is almost no currrent flow on these so no voltage drop. The power supply uses the sensed voltage to adjust its output so as to have the correct voltage at the lamps. Some remote sensing power supplies can operate with a single sense wire and a bit of electronic "mathmatics" in the controller.
     
  2. bernardgreen

    bernardgreen

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    This is just another example of incorrect terminology being used and the confusion it causes.

    As mentioned the supply cable from an "electronic" transformer ( properly called a Switch Mode Power Supply ) often has a maximum length. Three reasons are
    1/ reduce the amount of spurious radio frequency energy broadcast from the leads
    2/ reduce the voltage drop between supply and lamp
    3/ ensure the switch mode power supply can operate correctly

    1/ and 2/ are self explanatory.

    3/ needs some explanation. Connect a long lead to the output of a SMPS with the correct load at the supply end of the cable and nothing at the far end. With this configuration the SMPS may go un-stable due to the charactoristics of the un-terminated cable at the switching frequency of the SMPS. The voltage output from an unstable SMPS may go high enough to damage lamps.

    Voltage drop is the only problem when an inductive transformer is used with long leads. This can be compensated for by increasing the volage from the transformer. That does requires some care where a cable is feeding several lamps. If one lamp fails the current along the cable reduces and as a result the voltage drop along the cable reduces. The effect of this is that the voltage applied to the lamps that are still working is increased. In extreme ( and badly designed ) cases this increase may be enough to damage those lamps still working.

    lights_7.jpg

    372 incandescent lamps, 12-15 volt 2 watts each. Slightly under run at 9-10 volts to get the warm orange glow. ( without the disco lights the lamps made the perfect lighting system for the event )

    12 strings each with 31 lamps and 9 metres long then 6 metres to the power supply.

    372 transformer.jpg
    The transformer and fuse board to supply them. 2 pound coin for size comparison.

    A single SMPS would have been smaller and much cheaper, 12 separate SMPS units would also have been cheaper but both SMPS options created problems that made the SMPS options impossible to use.
     
  3. bernardgreen

    bernardgreen

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    That is proving a negative , cannot be proved. There is proof that using the wrong terminology has led to confusion when things do not work and the reason for the failure to work has become clear only when the correct terminology was used to describe items involved in the failure.
     
  4. ban-all-sheds

    ban-all-sheds

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    Nonsense. You are right that it cannot be proved, but the reason for that is that it is an utterly bogus claim, not because it's "proving a negative".

    These are my claims:

    • There is no remotely credible mechanism which would mean that a change in name would make DIYers aware of the potential problems with SMPSUs.

    • There is no remotely credible mechanism which would mean that a change in name would prompt DIYers to investigate and ask questions about the lighting power supplies which they want to buy.

    • There is no remotely credible mechanism which would mean that a change in name would stop unscrupulous manufacturers from making flaky products.

    • There is no remotely credible mechanism which would mean that a change in name would stop unscrupulous manufacturers from making false compliance claims.

    Clearly I can't prove any of them, because, as you say, how can one prove a negative? You, however, can prove that they are wrong by simply proving, or showing beyond reasonable doubt, the existence of such mechanisms.

    Will you do so?

    Can you do so?


    This is a DIY site.

    The issue is what should the little boxes which provide an ELV supply for lights be called.

    So thank you for moving us away from the "can't prove a negative" problem, and into an area where there will be no such problems.

    Within the context of the environment addressed by this site, which is where this issue is being argued over, please provide the proof that there has been such confusion etc. That is not "proving a negative", it is asking you to show us the proof that using the wrong terminology has led to confusion for DIYers when things do not work and the reason for the failure to work has become clear only when DIYers are told "it's not an electronic transformer, it is a switch mode power supply". NB - please don't rely on any explanation being given to said DIYers along with a name correction - the issue is what the devices are called, so the proof you need is proof that when the devices are "correctly" labelled then the confusion does not arise and/or the reason(s) for failure(s) become clear to DIYers.

    Don't you see? It is not the name of the item which matters. Do you really think that Mr Average, perusing the little white boxes on shelves in B&Q, or on a web page, would say to himself "Oh - that's a switch mode power supply, I'd better watch out about long leads on the output lest they radiate EMI or cause the device to become unstable in operation".

    Does anybody?

    The example you quoted (which the mods have not moved here) about the power supply for a baby alarm interfering with ATC radio traffic - do you really think that that interference would not have happened if the wallwart had had a label on it saying "Switch Mode Power Supply"? Does anybody?

    Don't you see? It is not the name of the item which matters. It is not the incorrect name which leads Mr Average to be unaware of the potential problems - if it were that would mean that Mr Average was simultaneously aware of the potential problems of switch mode power supplies and unaware that a little white box labelled "Electronic Transformer" was actually a SMPSU. Do you really think that is the case? Does anybody?

    It was not an incorrect label, or lack of a correct one, which led the maker to build something which did not comply with EMI directives. Do you really think it was? Does anybody?
     
  5. Gerrydelasel

    Gerrydelasel

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    If he knew a little about the practical use of SMPS then yes, absolutely. You can have basic knowlegde of that sort of thing and still be an average DIYer.
     
  6. bernardgreen

    bernardgreen

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    People have over the years installed transformers that did not create any radio frequency interference.

    They continue to install transformers today without realising that these transformers being installed today may disrupt radio communications.
     
  7. ban-all-sheds

    ban-all-sheds

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    For that to be the case it would mean that Mr Average DIYer was simultaneously aware of the potential problems of switch mode power supplies and unaware that a little white box labelled "Electronic Transformer" was actually a SMPSU. Do you really think that is likely?

    You see the sort of people we get here - what percentage of the general public do you honestly believe know about the practical use of SMPSs AND ALSO DO NOT know that an Electronic Transformer is one?
     
    Last edited: 14 Mar 2017
  8. ban-all-sheds

    ban-all-sheds

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    Dear God.

    You can keep on pointing that out for as long as you like, but every time you do I will ask you to explain the mechanism by which people who install "transformers" today without realising that these "transformers" being installed today may disrupt radio communications would suddenly, and without any extra explanations or education whatsoever, realise that they may cause disruption if only the label on them said Switch Mode Power Supply.

    And you may keep on completely ignoring that question for as long as you like, but it won't make your argument any more convincing.
     
  9. bernardgreen

    bernardgreen

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    This forum could do something to provide that education.
     
  10. ban-all-sheds

    ban-all-sheds

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    It could.

    But you are arguing in favour of "correct" naming on the grounds that that alone will stop people experiencing problems.

    Anyway - it prompts yet another question for you:

    • Please explain why such education could only take place if the little white boxes were labelled Switch Mode Power Supply instead of Electronic Transformer.

    Will you answer that one, or add it to the list of questions which you think you may just ignore because the answers won't suit you?
     
  11. Gerrydelasel

    Gerrydelasel

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    Yes absolutely. One plastic encapsulated cube looks much like another.
     
  12. ban-all-sheds

    ban-all-sheds

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    Are you sure you read that properly?

    You really think that the average DIYer knows about how to use/not use a switch mode power supply, and knows about their potential problems, but at the same time does not know that an electronic transformer is a type of SMPS?
     
  13. bernardgreen

    bernardgreen

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    You really are a pain in the proverbial.

    The education would include making it clear what the term "electronic transformer" meant.
    It would make it clear that the little box labelled "electronic transformer" had inside it electronic circuitry that generated interference that could affect other electronic equipment.
    It would make it clear that the amount of intereference and the area it affected would depend on how well the "electronic transformer" was designed and manufactured.
    It would make it clear that the area affected would also depend on how and where the "electronic transformer " was installed and for what purpose it was being used.
     
  14. Gerrydelasel

    Gerrydelasel

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    "I know a little about ordinary transformers.
    I also know a little about SMPS.
    This plastic cube says "electronic transformer" on it.
    My first assumption is therefore that it is a transformer (and not an SMPS)".

    Not exactly a leap of surrealism, is it?
     
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  15. ban-all-sheds

    ban-all-sheds

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    So therefore it would make no difference whether the label on the little box said [Electronic Transformer] or [Switch Mode Power Supply] - you could still perform the education.


    It would make all of those things clear no matter what term you had to put inside those quotes:
    • It would make it clear that the little box labelled "electronic transformer" had inside it electronic circuitry that generated interference that could affect other electronic equipment.
    • It would make it clear that the amount of interference and the area it affected would depend on how well the "switch mode power supply" was designed and manufactured.
    • It would make it clear that the area affected would also depend on how and where the "power transmogrifier" was installed and for what purpose it was being used.

    Don't you see?

    The name has no bearing on what the device does.
    The name has no bearing on how it does it.
    The name has no bearing on what the potential problems of it are.
    The name has no bearing on what education people need to understand how it works and what problems it might create.

    The fact that you talk about educating people shows that you don't actually believe that they will know these things unless they are told them. This "confusion" would happen no matter what the little boxes were called. It happens not because calling them something you don't like makes people not know what's inside the little box or how it does it's stuff, but because people don't know those things no matter what they are called.

    Time and time again you have refused to even attempt to show that Mr. Average knows full well what a switch mode power supply actually is, how it works, and how it can cause problems.

    You have refused to even attempt to show that the ATC radio interference by the baby alarm PSU happened because it was not labelled "switch mode power supply".

    When I asked you to "please explain why such education could only take place if the little white boxes were labelled Switch Mode Power Supply instead of Electronic Transformer" you talked about what the education would cover, but you didn't even attempt to answer the question.

    Do you really think that if you wandered about the aisles of B&Q (other sheds are available) on a Saturday afternoon, and until you were asked to leave asked the Mr. & Mrs. Average People browsing in the lighting department if they knew what a switch mode power supply was, and what issues they should be aware of when using them to power lights, you'd find many that did?
     
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