Help with my rats nest!

Discussion in 'Instruments / Avionics / Electrical System' started by pequeajim, Jan 13, 2008.

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  1. Jan 13, 2008 #1

    pequeajim

    pequeajim

    pequeajim

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    I have a problem.
    In wiring the 12 Thermocouples for my Jabiru 3300 to my RDAC, I find that there doesn't seem to be a way to keep everything neat.
    I have extended the wiring for two of the TCs, but some of the wire is too long and I have to coil it. Now I basically have a rats nest around the RDAC>
    THis is the first engine that I have wired up. Can anyone suggest a good solution? I don't think I can cut the TC wires to make it neater, can I?
    Any help would be appreciated...

    http://f1.grp.yahoofs.com/v1/sH6JR_...SSV4BJdCcT/Jim's Lightning/RDAC Rats Nest.JPG
     
  2. Jan 13, 2008 #2

    CESSNADON

    CESSNADON

    CESSNADON

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    Generally speaking, digital tc readouts are not sensitive to lead length as are the analog types. Your best bet is to contact the manufacturer and ask the question. If you cut the leads you need to use the same type terminations as the original. Tc terminations are usually made of the same material as the wire to minimize errors in the system.
     
  3. Jan 13, 2008 #3

    pequeajim

    pequeajim

    pequeajim

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    Thanks Don>

    The EFIS that I am using has internal cold compensation. I just read the Thermocouple chapter in the Aeroelectric book, www.aeroelectric.com/articles/excerpt.pdf

    Very informative reading. Anyway, it appears that I can indeed cut the wire short, and even if necessary, extend some of the TC wiring I have, as long as I use the same type.

    To build extensions, he prefers that you solder them together using solver solder. I think I should be able to crimp the wire together as long as I twist the wires that I am connecting together before applying the crimp.
     
  4. Jan 14, 2008 #4

    CESSNADON

    CESSNADON

    CESSNADON

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    I agree, twisting the wires tightly and crimping them should work. I would offset the joints and sleeve each joint and the overall wire with shrink tubing to reduce the oxidation. I'm guessing that you have type K, chromel/alumel which has a red and a yellow conductor and quite resistant to corrosion. You might also want to check Omega Engineering. They carry thermocouple connectors that are good for what you are doing.
     

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