False Triggering on Solenoid Circuit

Discussion in 'General Electronics Chat' started by Otto, Dec 30, 2008.

  1. Otto

    Thread Starter New Member

    Dec 27, 2008
    Need some suggestions on how to eliminate "false triggering" of the solenoid on the attached single line/block diagram. This circuit is installed in a house and operates as intended, but when an exhaust fan is switched on (in-rush) somewhere in the house, the solenoid is activated. Looking for a type of filter -or- suppression circuit to add to the original circuit. Thanks.........
  2. Alberto

    Active Member

    Nov 7, 2008
    The block diagram doesn't say much! Important to know is the shematic of the infrared circuit and the solid state relay. Just for trail you could install a capacitor of 0.1 microfarad X2 rated on the secondary of both the tranformer, to block possible interference coming from the main.
    If this is not enough, then a deep exam of the circuitry is mandatory.

  3. drc_567

    AAC Fanatic!

    Dec 29, 2008
    It sounds like the exhaust fan motor .... typically an induction motor, is causing a voltage instability either on the DC supplied board, or on the solid state relay. When an induction motor turns on, there is a large current drain that lasts for a few seconds. This event is likely the cause of the problem. Is there a sufficiently large electrolytic capacitor on the input to the DC supplied board? .... Such a capacitor might even out any temporary voltage anomaly. Check any wiring hook-up connections on the solid state relay .... no corrosion or oxidation .... use a contact cleaner spray ....
  4. Otto

    Thread Starter New Member

    Dec 27, 2008
    Thanks for the replies. I only have a hard copy of the schematic and my home scanner is not operational, so as sson as I get it up and running I will post the entire circuit. In the mean time I will try the capacitor....thanks again!