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Low voltage indicator lamp of 110vac circuit

Discussion in 'General Electronics Discussion' started by 12vdc, Sep 16, 2018.

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  1. 12vdc

    12vdc

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    Apr 13, 2011
    This is a bit weird

    I have a 110vac switch to turn on and off a well water supply pump.

    it breaks the "hot" side before feeding the pressure power switch.

    is there a way to have an indicator lamp (led or incandescent) using the "earth/box ground"?

    I need to indicate the the pump potentially could operate or be operating.
     
  2. Bluejets

    Bluejets

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    894
    Oct 5, 2014
    No, the ground line is there for protection during fault conditions, not for general power supply connections.
    Any indicator would need to go across the switched line and neutral.
    There are low voltage, non-invasive circuits around, I believe one cropped up a couple of weeks ago.
    Fairly simple arrangement from memory.
    Others will know where to find it in the discussions here.
    Basically worked by wrapping an insulated wire around the switch wire active.
     
  3. duke37

    duke37

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    Jan 9, 2011
    You could put a current transformer at the switch driving a led, so indicating passing current. It may be possible to monitor the current and detect if the pump is stalled.
    The only best way is to measure pressure.
     
    twister likes this.
  4. Bluejets

    Bluejets

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    Oct 5, 2014
    Reference to #2, found the link.........

     
  5. Externet

    Externet

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    Aug 24, 2009
    Five neon pilot lamps can be used,

    Hot------------A-----------switch------------B-----------Pressureswitch---------C--------pump---------N eutral

    A pilot lamp between A and N will tell the mains is good.
    A pilot lamp between C and N will tell the pump is energized.
    A pilot lamp between B and C will tell the pressure has been reached and pump is off.
    A pilot lamp between A and B will tell the power switch is off and pump is enabled to run.
    A pilot lamp between B and N will tell the pump is enabled.

    Implement as many as you want, green, red,... wired, spade,...


    [​IMG]
     
  6. Bluejets

    Bluejets

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    Oct 5, 2014
    I have the impression the Op wants to operate the indication remotely hence the original request for using the earth wire as one signal return.
    Who knows as there has been no reply.
     
  7. 12vdc

    12vdc

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    9
    Apr 13, 2011
    Yes bluejets is correct, (I no longer have my dialup ISP, I was his last client) so I take a day or two to reply.

    I was hoping not to have to run additional wiring to the remote switch for the lamp.

    my simplest idea was to connect a wall wart to the pump connections and run the low voltage (3vdc) by light gauge wire to an LED. the indicator is to remind us to turn off the pump when we leave the house the to avoid floods or running the well dry should a line leak.

    Thanks for input so far.
     
  8. Externet

    Externet

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    162
    Aug 24, 2009
    If you plan to run light gauge cable; cat3+ cable is cheap and could provide several conductors for signaling, even control a remote relay to turn the thing on/off from inside the house.
    If the concern is running the well dry, a float switch in series could take care of that.
     
  9. 12vdc

    12vdc

    46
    9
    Apr 13, 2011
    The pump is in my basement and the well is 60' away underground from the pump.
    A float switch is not possible (have to dig up well cover below ground) we have sand in our well and it eventually eats holes through the piping so I wish to be reminded that the power to the pump is live and to shut it off when not in use. (a lame version of "on demand" water) the cat3 cable is a good Idea.
    (I was researching the use of a solidstate relay to replace the light switch I currently use to break the circuit, something for a later date)
    thanks
     
  10. Bluejets

    Bluejets

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    894
    Oct 5, 2014
    So you only wish to monitor that power is available to the pump via the isolator switch and NOT that the pump is actually running.???
    So where is the switch and pump located in respect to eachother, where do you require the warning light to be and where is the power fed from??
    Perhaps a pencil sketch of what is where and what you have in mind would be a great help.
     
  11. 12vdc

    12vdc

    46
    9
    Apr 13, 2011
    The switch is 20 feet from the basement pump upstairs. The pressure switch is unpredictable due to the sediment build up. Sometimes the pump will run for many minutes with no water flowing and the motor gets hot. trying to prevent failure.

    We live where having water in the well during the summer is a sign of good luck, some neighbours have none since may.

    I made an error, I want replace the pressure switch with a solid state relay (not the override switch I installed) and eventually have a floor mount push button for true on demand for the sinks and the manual switch for shower, toilet and washer.
     
  12. Bluejets

    Bluejets

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    894
    Oct 5, 2014
    So now the low voltage indicator is out.........

    and you now want to by-pass the pressure switch ......

    and have the pump manually run from 4 locations......???

    Yes, can be done but not without running cabling ......

    /or using some form of wireless control.

    Depends on the size of the pump as to the size of the control relay/contactor/ or if you must, ssr relay.

    You do know there are control relays that can detect either presence of water or pressure/lack of at start-up and operate the pump/or not depending on circumstances...would negate the requirement for all of these hack manual mods.
     
  13. twister

    twister

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    Feb 12, 2012
    I use a 20K ohm resister and a LED between the switched line and neutral. Use a smaller resistor if LED too dim.
     
  14. duke37

    duke37

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    Jan 9, 2011
    Normally, a pair of diodes in inverse parallel is used so that each diode protects the other ffrom excessive voltage.
     
  15. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Do yourself a favor and remove the pressure switch and replace it with a float switch.
     
  16. twister

    twister

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    Feb 12, 2012
     
  17. 12vdc

    12vdc

    46
    9
    Apr 13, 2011
    Sorry, you would think english was greek to me...
    I cannot add a float switch, the well is 40' deep and the well cap is 6' ft below ground, buried.

    I don't mind running cable, but do not want to run 110vac,

    If i get a solid state relay I can trigger with 12vdc then the cables and additional switches are easy.

    I like the LED/resistor (maybe with diodes as stated) but like I original asked what is the issues of connecting it Line to earth ?
    (maybe fuse it to be safe)

    thanks
     
  18. Bluejets

    Bluejets

    4,219
    894
    Oct 5, 2014
    Keep away from connecting to the ground wire. Already told you about that.
    It's there for fault current conditions and connecting there can be dangerous.
     
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