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12 VDC interposing relay (OT)

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  • 12 VDC interposing relay (OT)

    I have a friend that is looking for a 12 VDC interposing relay to operate the AC DEC motor with DC control voltages on a old telescope. I thought someone here might be able to help?


  • #2
    Go to Search for relay. Scroll down to the "relay" section in the results.

    When the selections of relays appears, select "Power over 2 Amps @30VDC".

    Now under coil Voltage select "12VDC" and click apply filters.

    At this point I got 1471 results, "Spaning 59 pages" all of which meet your specs so far. You are going to have to be a bit more specific. Motor current? Number of contacts (1, 2, etc)? Type of mount? Termination style? BYW, you can sort by price when you view the actual pages of parts.

    You don't have to buy from them, but it is a great site for finding a part that will work to your specs.

    Mouser is similar.

    Many other sources if you find these prices too high.
    Paul A.
    SE Texas

    And if you look REAL close at an analog signal,
    You will find that it has discrete steps.


    • #3
      Cars these days have banks of 12 volt relays in the fuse box. Many of them have very high rated contacts to run loads such as wipers, blowers and power seat motors etc. They are also very compact. Try an auto wrecker.

      Relays such as these which are intended to operate large inductive loads will have plenty high enough voltage ratings to operate a light load at 117 vac.
      Free software for calculating bolt circles and similar: Click Here


      • #4
        Thanks for the help, I will let you know how it goes.



        • #5
          His decision was ...... to use two relays using diodes as logic elements (sort of). Depending on the polarity of the DC output of the DEC cable, as determined by which button is pressed, one relay will turn on and the other will not "see" the applied voltage., so it will not pick up. The relay that does operate will apply the hot AC voltage to one side or the other of the motor leads and so will turn the motor CW or CCW, again depending on which button you pressed.

          Thanks for the link Paul and suggestion Evan,