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  1. #14
    Join Date
    Mar 2005
    Pacific Time Zone
    A one button reset spec'd. I would likely just bring the safeties into a PLC and have the one button reset to come into the PLC as well. Then I would back up that series of botd's with multiple other safeties in the logic.
    What about letting it alarm out - Freezestat/Powerfail Alarm Requires Manual Reset!
    Not ideal I know, but how often do they have power bumps? Don't know your climate, but this may/may not be acceptable in case of a long weekend.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
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    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform - not my website.
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  2. #15
    Join Date
    Nov 2009
    West Yorkshire England
    Would a latching relay be an option? Like flyin90 says could you explain the circuit more in detail or maybe show a drawing so everyone can help you further.

    50 & 60 hz but 100's worse

  3. #16
    Join Date
    May 2008
    Jax Fl.
    Omron makes some small self-powered time delays that will continue to operate for up to 10 minutes without any power on them. They work very well.

  4. #17
    Join Date
    Mar 2008
    Quote Originally Posted by JRINJAX View Post
    Omron makes some small self-powered time delays that will continue to operate for up to 10 minutes without any power on them. They work very well.
    This sounds like the ticket if it fits the application. I have used them but did not know who made them.

  5. #18
    Join Date
    Jul 2009
    Alexandria, VA
    A better UPS will resolve the problem.

    Make sure that auxillary transformers (if used for this circuit) are on the UPS power. Often I will find the DDC control cabinet on UPS power but not the external devices.

    Quote Originally Posted by lumpsum View Post
    So we have a circuit that consist of simply 5 botd devices (break on temperature drop) "Freeze Stats". The unique thing about this circuit is that there is a reset in the control panel so the voltage runs through the freeze stats and when on trips.... the relay opens the entire circuit. So we have an uninterpretable power supply and when we lose power the UPS take approx. 30 milliseconds to kick power to all the devices on it. During this time the relay loses power and it acts as if a freeze stat has tripped. The job was speced for this "one button reset".

    Does anyone have an idea how to keep power to the relay for 30-100 milliseconds while power from the ups is kicking in?

    We have already tried a small 63 volt dc non polarized capacitor. This does not work.

    Any ideas would be greatly appreciated!!!

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