Re: Delay on a mains-powered relay?

From: Fred Bloggs (nospam_at_nospam.com)
Date: 01/05/05 

Date: Wed, 05 Jan 2005 13:25:31 GMT

>
> If power fails at the remote site, so does the control circuitry and its
> power. So a traditional delay relay won't work.
>
> The relay, powered by mains, simply opens the wireless sensor's sense circuit
> when power goes away. I just want it to do so after waiting a few minutes to
> see if power comes back on.

The wireless "sensor's sense" ciruit is most likely something with a
weak pull-up of say 100uA, so that shunting the relay input terminals
with C=100uA/(3V/300secs)=10,000uF 10WVDC should get you close:
      View in a fixed-width font such as Courier.

                  +--------[100]--+------->
                  | |
                  o | +
                   / === to sensor
                  o | 10,000u
                  | |
                  +---------------+------->

Relevant Pages

  • Re: NOW: Fuel Pump Install...WAS: EGR VALVE! 87 Golf
    ... This eliminates faulty wiring and insufficient power and then I can ... I usually use a jumper wire after I remove the relay to supply power to the ... Then at the pump connect ... lead of the test light to. ...
    (rec.autos.makers.vw.watercooled)
  • Re: 4017 Counter skips under load
    ... But when I try to operate the circuit under load ... skips the loaded relay and moves right to the next output. ... Think "star grounding" and power decoupling. ... with the slightest change in ground (even connecting a single lead ...
    (sci.electronics.design)
  • Re: Rotation detection?
    ... Leave the keys long, place a roller limit switch against each shaft so the keys trigger the switch. ... Install one dpdt relay in the power line to the motor. ... Wire it so power flows to the motor in the NC position. ...
    (rec.crafts.metalworking)
  • Re: Remote Power Supply Connection
    ... under the cover is a micro switch. ... DC power requires ... That pulls in a relay that connects the B+ ... input pinto the B+ line in the amp. ...
    (rec.audio.tubes)
  • Re: Dell Trinitron 17" flaky - worth repairing?
    ... There was no change in the picture before ... At the same time the picture went black the green light on ... > the power button also went out. ... I did hear a relay click out, as is normal when you shut it ...
    (sci.electronics.repair)