Patent ID: 7571597

Claim:
An aircraft lubrication supply system, comprising: a motor coupled to receive motor speed commands representative of a commanded motor speed and operable, in response thereto, to rotate at the commanded motor speed and supply a drive force; a pump having at least a fluid inlet and a fluid outlet, the fluid inlet adapted to couple to a lubricant source, the pump coupled to receive the drive force from the motor and configured, in response thereto, to draw lubricant from the lubricant source into the fluid inlet and supply lubricant, via the fluid outlet, to a rotating machine; a lubricant filter having a filter inlet and a filter outlet, the filter inlet coupled to receive at least a portion of the lubricant supplied via the pump fluid outlet, the lubricant filter configured to filter the lubricant received thereby and discharge filtered lubricant via the filter outlet; a filter inlet pressure sensor disposed upstream of the filter inlet, the filter inlet pressure sensor configured to sense filter inlet pressure and supply a filter inlet pressure signal representative thereof; a filter outlet pressure sensor disposed downstream of the filter outlet, the filter outlet pressure sensor configured to sense filter outlet pressure and supply a filter outlet pressure signal representative thereof; a motor control unit coupled to receive the filter inlet pressure signal, the filter outlet pressure signal, one or more signals representative of lubricant temperature, a signal representative of rotating machine rotational speed, and one or more signals representative of aircraft operating conditions, the motor control unit operable to: (i) determine a scheduled lubricant supply pressure based at least in part on the lubricant temperature, the rotating machine rotational speed, and the one or more aircraft operating conditions, (ii) supply motor speed commands to the motor that cause the pump to supply lubricant at the scheduled lubricant supply pressure, (iii) implement a closed-loop pressure control law that uses a pressure feedback signal to determine actual lubricant supply pressure, (iv) compare the actual lubricant supply pressure to the scheduled lubricant supply pressure, and (v) determine operability of the filter outlet pressure sensor, wherein the motor control unit uses the filter outlet pressure signal as the pressure feedback signal if the filter outlet pressure sensor is determined to be operating properly and uses the filter inlet pressure signal as the pressure feedback signal if the filter outlet pressure sensor is determined to not be operating properly.