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Time Delay Relay

  1. Jan 24, 2010 #1
    What is a Delay-On-Dropout-Timer relay. Is this what can be used for a glow plug timer?
  2. jcsd
  3. Jan 24, 2010 #2


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    From the sound of the description I would assume that when you energize the coil the contacts shift immediately. When you remove power from the coil the contacts don't shift until a predetermined time has elapsed.
  4. Jan 26, 2010 #3
    It is an especial time relay which applied in special control or protection circuit. we usually aspect the relay dead situation when we deenergize its bobbin( or active part) immediately, but timer with drop off time delay have an inherent delay for reverse to dead condition( NO/NC contacts) after deenergizing.

    Creative thinking is enjoyable, Then think about your surrounding things and other thought products. http://electrical-riddles.com
  5. Jan 30, 2010 #4
    Is there a terminology for a relay that will be on for a set period of time when the power turns on and then shuts off until the power is turned off and back on?
  6. Jan 31, 2010 #5
    TDE = Time delay energize
    TDD = Time delay de-energize

    These terms harken back to the days of mechanical oil-flow electrical timers.

    Modern timer relays are electronic & universal function. Omron is a major brand.

  7. Jan 31, 2010 #6
    So TDD would be what I am looking for?
  8. Jan 31, 2010 #7
    Last edited by a moderator: Apr 24, 2017
  9. Feb 1, 2010 #8
    An Omron H3CR-A can operate in any mode you might need. It's all in the data sheet. Make sure the timer you select will operate at the voltage of your system.
    http://www.ia.omron.com/data_pdf/data_sheet/h3cr-a_ds_csm85.pdf" [Broken]

    You need to be careful, as a diesel engine's glow-plugs can pull pretty heft current (30A), much more than a timing relay's contacts are rated for. If so, then you need to have a slave high-current relay as well.

    Or, just use a momentary push-button rated for the current required. Let the analog computer inside the ol' noggin do the timing. This is typical for glow-plugs. Available at your local auto-parts store.
    Last edited by a moderator: May 4, 2017
  10. Feb 1, 2010 #9


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    Thornton why do I get the feeling you are connected with the company Omron? To the OP, industrial timers are pretty standardized. No need to go with a specific brand.
  11. Feb 1, 2010 #10
    No company connection
    This brand is what we typically use at my work because they do the job, and available from my local electrical supplier. I was just trying to point out that modern timer relays are often universal function, using the linked item as an example.
    My recommendation of using a simple push-button (for glow-plugs) is illustration of adherence to the KISS principal... no timer required at all.
  12. Feb 1, 2010 #11


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    This would be my recomendation as well. A warm engine does not need glow plugs on as long as a cold one, that is if they need to be on at all.
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