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Wrong wiring??

Discussion in 'General Electronics Discussion' started by Jbrt, Jul 13, 2019.

  1. Jbrt

    Jbrt

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    Feb 16, 2018
    I purchased 2 textile cleaning guns for the use of cleaning mineral specimens. The momentary push button switches overheated and eventually ceased altogether. I could not get these switches anymore so I purchased rocker switches. When I opened up the guns, I noticed that the neutral wire leeds to the switch and not the live. As I understand, the live has always got to leed to the switch. Is this wiring on the machines wrong (as I suspect) or am I missing something? I will appreciate help.
     

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  2. bushtech

    bushtech

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    Sep 13, 2016
    To be correct the brown and blue incoming wires should be swopped over in the device. That would make the Live wire switched instead of the neutral.

    The overheating push button switches could be caused by underspecced switches or there is something wrong with the device and it is drawing more amps than the switch can handle.
     
    davenn likes this.
  3. Jbrt

    Jbrt

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    Feb 16, 2018
    Thank you Bushtech. That is what I thought. Are there any exceptions to breaking a live with a switch instead of the neutral? Why on earth did the manufacturers wire the machines like that???
     
  4. bushtech

    bushtech

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    Sep 13, 2016
    I can't think of any reason to switch neutral instead of live. Maybe one of our more knowledgeable members can help.

    Maybe the power cables got replaced somewhere to make them fit the plugs in SA. And the person doing it didn't know how/ didn't care/colourblind:)
     
  5. Jbrt

    Jbrt

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    Feb 16, 2018
    Thank you Bushtech! I would be interested to hear from other members too. I have always believed that a simple on and off switch has to break the live. It seems like common sense, but I want to be absolutely sure.
     
  6. Bluejets

    Bluejets

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    Oct 5, 2014
    Cheap jack gear.

    Actually on portable equipment run on a flex and plug should have double pole switching.
    i.e. active and neutral both.
     
    davenn likes this.
  7. Martaine2005

    Martaine2005

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    May 12, 2015
    Why can you not get these anymore? It is only a panel/chassis mount momentary switch. Perhaps you kept that switch on for longer than the specified time.
    More than likely.
    My thoughts exactly.
    Some items/devices have the neutral switched too via a DPDT instead of the usual SPST switch.

    Martin
     
  8. Jbrt

    Jbrt

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    Feb 16, 2018
    Hi Martaine, there is no time specified. I would think that the working mechanism would overheat and not the switch. I believe the switch is too light for the amperage. These machines are not made to be used as we use them to clean mineral specimens. They work much harder, but the switch should be able to bear up.These rocker switches have a higher amperage and I am hoping they will last longer.
     
  9. dave9

    dave9

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    Mar 5, 2017
    I know nothing of textile cleaning guns or mineral specimens, but...

    - Live should be switched to minimize risks of having the rest of the circuit and chassis life relative to earth ground, but it would work either way electrically, and given a metal case it ought to be earth grounded, not a two wire cord.

    - What is the origin of this equipment? Was it bought new and known NOT to be subject to repair already? I am wondering if the original grounded 3 wire cord got damaged (or rewired for SA outlets as bushtech mentioned) and was replaced with a 2 wire cord that was wired backwards with neutral going to the switch.

    - The switch does not look special, I mean as Martaine mentioned you should be able to find a replacement.

    - If you're using these for an unattended purpose with a higher duty cycle, sure they may not be built to withstand that. A higher rated switch might help, or running longer may just make something else overheat.

    - The following page states "cleaning them with water will spell certain doom". That may not be what you're doing, but since this is new to me, I mention it:

    http://www.mcdougallminerals.com/blog/caring-for-mineral-specimens/
     
  10. bushtech

    bushtech

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    Sep 13, 2016
    jbrt: I think that you are not using them for their original intended use. The fact that they came with a push button would imply short usage times. Were you holding down the push buttons for minutes at a time? A push button is not meant for that. Then a switch is normally employed.
     
  11. Jbrt

    Jbrt

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    Feb 16, 2018
    Hi Dave, thank you for your reply. The origin is China. These machines are commonly used for cleaning minerals. I am a mineral dealer so, fortunately I know which minerals can be cleaned with water.I also wondered about the fact that these machines come out without an earth. I will rewire them completely and include an earth wire to the chassis. These machines arrived in SA like that. It is possible that they were wired for the SA market but it now appears that they are wired wrong. Yes, I push them harder than what they are made for, but I do not mind if they perish as they are not expensive and do a very good job cleaning crystals (see example of a self collected piece)
     

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  12. Jbrt

    Jbrt

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    Feb 16, 2018
    Hi Bushtech, I knew that from the beginning, but suspect that these switches are inferior. It is very difficult to get these switches locally. None of the sellers of these machines, not even in China, wants to help. To import them from USA is quite expensive. I don't mind too much if these machines burn out as they have already paid for themselves in work and are not expensive.
     
  13. bushtech

    bushtech

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    Sep 13, 2016
  14. Jbrt

    Jbrt

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    Feb 16, 2018
    Yes, thank you. I visited a few large suppliers but none had anything decent besides these rocker switches (see photos). Can you foresee any trouble using these? They have a higher amperage than the existing ones.
     

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  15. dave9

    dave9

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    Mar 5, 2017
    Often with switches, it matters a lot to get a quality brand (and new stock, not new/old stock) if you're subjecting them to much current or on/off cycles. A generic can claim 10A (or whatever) and do that initially, but not last long. At least it's AC instead of DC.

    Unfortunately I know nothing about suppliers in your region, but if you are not in a hurry to receive them, there are many component sellers on ebay that will ship internationally, or nearly so. Then the question becomes Are you paying more for a genuine major brand or is it a counterfeit part, so it is good to try to find a reputable seller, and you may still have an issue with a part being called "new" when it has sat in a bin who-knows-where for a decade and have fouled contacts.
     
    Last edited: Jul 13, 2019
  16. Jbrt

    Jbrt

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    Feb 16, 2018
    It is true Dave, a good switch is a good start. There are Textile guns in USA that are far more superior but, to import spare parts that may match the one I have, is very expensive (mostly postage).
    From the advice I gathered so far, I will rewire the machine with a 3 core cable and stick with the switches I have and rest the machine more often.
     
  17. Bluejets

    Bluejets

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    Oct 5, 2014
    Baaaad idea if the unit is double insulated.
    Look for any sign of double insulated logo on the label.
    One square inside another square.

    Far better to make certain the circuit you are operating the device on, has an earth leakage breaker(safety cut, safety switch...all the same)
    Failing that there are portable units available.
    Might be $80-$90 but ...........you are operating around water after all.
     

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  18. dave9

    dave9

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    Mar 5, 2017
    ^ Look at the pics, you can see it clearly is a metal handle right where the wire junction is! Not double insulated.

    It would also be good to use it on a ground fault outlet considering water or whatever liquid is involved. I've no idea what they cost in SA but in the US they can be had for about $12 USD on Amazon, hardware stores, etc.
     
  19. Bluejets

    Bluejets

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    Oct 5, 2014
    $12.00......mmmm... not sure I'd trust any family member/work college of mine with that either.
     
  20. dave9

    dave9

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    Mar 5, 2017
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