Specialised lamp tester

Discussion in 'General Electronics Chat' started by bitbrat, Nov 10, 2009.

  1. bitbrat

    Thread Starter New Member

    Sep 29, 2009
    3
    0
    OK so I have been looking all over, I have heard about simple testers using op-amps, windo comparators etc. but can't seem to work this out...

    In my industry (entertainment lighting) there is a specialised need for a tester that checks 6 circuit "multi-cable". These cables could have almost any compbination of series or paralell incandescent lamps connected to them - all 120v types, many possible wattage combinations. However, as well all know the resulting resistance will be very low, but NOT dead short.

    There are commercial testers out there that use bi-color LEDs to show the state of any given hot/neutral pair of connections on the 6-circuit connector:

    - Green for a good lamp (low resistance)
    - Red for a short (no resistance, sometimes also sounds a piezo sounder)
    - Off for open circuit

    I don't know if the LEDs are two wire or three wire.

    I do know that the ciruit has a very low quiescent state current - so if it is not testing anything it is essentially "off" drawing little or no current.

    I know that the circuits are small, I mean low component count, because they fit inside an amphenol 19 pin connector (called socapex) and these things are a tight fit once you shove a battery in there as well!

    Anyone? Help would be greatly appreciated....

    :confused:
    Andy
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Are you talking about these?
    link: http://www.lexproducts.com/galleries/product_document_public/6 Circuit Live Tester User Guide.pdf

    Not cheap, at about $275/each - and all they are is a connector with LEDs, diodes, and current-limiting resistors - however the cost is high because there would not be a big demand for them.

    The LEX tester doesn't require batteries; you disconnect the load end and leave the other end live. That would verify the hot/neutral/ground to the load end, but not check the load end for shorts/opens/etc.

    Are you saying that their is no tester available for checking the load end from the powered end?
     
  3. bitbrat

    Thread Starter New Member

    Sep 29, 2009
    3
    0
    OK, sorry, I am bumping this....

    I got pulled away from this by some major issues of "real life" - now back to it.

    SgtWookie - many thanks - you're quick on the uptake, but this is the right style connector, wrong type of tester - the one I need to make tests the lights that you would plug in to those six circuits. eg:

    http://www.toolsforstagecraft.com/meters-socapex.htm

    I would like to know how the circuit works.. I know I should just shell out the $110 and look for myself (assuming they haven't "disguised it at all") but I work with these components all the time, especially the connectors which are the most expensive piece..

    Any ideas??

    Thanks in advance,

    Andy
     
  4. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    I have seen some Socapex "Grenades" for testing socapex wiring pairs and checking for lamps on the end of each circuit..... is that what you are looking for??

    here is some info from another forum that specializes in DMX lighting and other stage stuff....


    just don't plug it into a live male plug :eek: This is strictly for checking for lamps on the end of the circuit or checking cables with the male shorting cap......


    I hope this helps......

    You might also find an old set of these connectors and use those.... I am sure you have some damaged cable assemblies laying around that no one would miss :cool:....

    My .02
     
    Last edited: Nov 22, 2009
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The link you posted didn't work.

    I think this is what you're talking about:
    http://www.toolsforstagecraft.com/meters-socapex.htm

    If the connectors are the most expensive part (which I most sincerely would not doubt) then these things are a remarkable bargain.

    Trying to build them yourself would cost much more in the hours invested than the purchase price, and your failure rate would certainly be much higher.

    Building them yourself would simply raise the cost of acquisition for others; as fewer testers would be sold.
     
  6. bitbrat

    Thread Starter New Member

    Sep 29, 2009
    3
    0
    so yeah, as usual, I don't get on here much.... but...

    You are right on the money, it is a socapex style tester... and yes, I can buy them, or even make them (I have the connectors in stock), what I am trying to work out is this:

    The basic testers just check for a low resistance between the live/neutral pairs in the connector (1+2, 3+4, 5+6 etc.), but as you can see on toolsforstagecraft you can get testers that will distinguish between open circuit (no light), good lamp (green light), and short (red light/buzzer).

    I am wondering how they do this? I know they are using bi-color leds, and some sort of window comparator or even simpler circuit, any ideas?

    AJ

    P.S. I am trying to build a more sophisticated bench mounted tester that will do all sorts of tests, including other connectors, like stage pin, edison, twist lock, etc. so we can have a kind of all purpose cable/lamp testing bench tool.
     
    Last edited: Dec 14, 2009
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