Patent ID: 6237420
Filing Date: 2001-05-29
Classification: G05B

Abstract:
Oil condition detection apparatus for use in compressor systems comprising:a microcontroller having input ports and output ports, an AC voltage power source, a full wave rectifier coupled to the AC voltage rectifier, the rectifier having an output providing a signal RLAY.sub.- PWR, a first current limiting resistor serially connected to the rectifier output to provide a signal VDD.sub.- SENSOR to power a pressure sensor, an isolation diode having an anode and a cathode, the anode connected to the rectifier output, the cathode connected to a second current limiting resistor which in turn is connected to the cathode of a 5 volt zener diode, the anode of the 5 volt zener diode is connected to ground with the 5 volt zener diode providing a regulated DC voltage signal VDD connected to an input port of the microcontroller, a storage capacitor coupled between the cathode of the isolation diode and ground to provide power to the microcontroller for a preselected time upon power interruption,a pressure sensor having electrical contacts movable into and out of electrical engagement in dependence upon the oil pressure level in a compressor to indicate either a good oil condition upon sufficient pressure or a bad oil condition upon insufficient pressure, the VDD.sub.- SENSOR signal coupled to a pressure sensor electrical contact, another pressure sensor contact coupled to an input of the microcontroller to accumulate good and bad oil condition times,the microcontroller having an interrupt input port coupled to AC voltage, the microcontroller normally being in a sleep mode and being awakened on each cycle of the AC voltage source wave to detect selected functions including the oil condition, and then reverting back to the sleep mode,the microcontroller having an output port connected to a device for shutting down the compressor system whenever selected oil condition times occur.