Patent ID: 7026729
Filing Date: 2006-04-11
Classification: F24F,G04F,G04G

Abstract:
1. A load activation and variable grace period timing system for use with an exhaust fan comprising: an exhaust fan; a monitor for detecting when a lamp switch is activated and providing an output signal at a first level representative thereof; a timer comprising a pulse generator and a counter, said pulse generator being an analog oscillator including means for varying the frequency thereof, said frequency changes determining the variable grace period, said counter receiving the output of said pulse generator, said timer receiving said output signal of said monitor to activate said pulse generator but to disable said counter so long as said first level output signal is applied, said counter being enabled when said lamp switch is deactivated and said monitor output signal level changes to a second level so that said counter counts said pulse generator output for a predetermined preset but variable time; and a power switch for applying electrical power to said load including said exhaust for when said monitor output signal is at said first level and continuing until said counter reaches said predetermined count.