Aircraft brake cooling fan control system

Abstract

An aircraft includes a power source arranged to provide AC electrical power of varying frequency, and a brake cooling fan including an impeller which is driven by an electric motor powered by said AC electrical power for cooling brakes of the aircrafts wheels. The brake cooling fan has an operable mode when the frequency of said AC electrical power meets certain criteria indicating that the frequency of the AC power is suitable for powering the motor, and an inoperable mode to protect against unsuitable operation of the motor. The brake cooling fan may then be safely powered with AC power direct from a wild frequency power network on the aircraft without needing a power inverter or constant power supply generator.

1 . An aircraft including:
 a power source arranged to provide alternating current (AC) electrical power of varying frequency, and   a brake cooling fan including an impeller driven by an electric motor powered by the AC electrical power,   wherein the brake cooling fan is arranged to have an operable mode selected when certain criteria are met, the criteria including whether the frequency of the AC electrical power is suitable for powering the motor, and   the brake cooling fan is arranged to have an inoperable mode selected when the certain criteria are not met and to protect against unsuitable operation of the motor.   
     
     
         2 . The aircraft according to  claim 1 , wherein the certain criteria include whether or not the frequency is less than a maximum amount. 
     
     
         3 . The aircraft according to  claim 1 , wherein the certain criteria include whether or not the frequency has been less than a threshold amount for a certain period of time. 
     
     
         4 . The aircraft according to  claim 1 , wherein the aircraft is so arranged that the inoperable mode of the brake cooling fan is triggered if the frequency of the AC power is not suitable for powering the motor. 
     
     
         5 . The aircraft according to  claim 1 , wherein the aircraft is so arranged that the inoperable mode of the brake cooling fan is triggered if the aircraft is not on the ground. 
     
     
         6 . The aircraft according to  claim 1 , wherein the aircraft includes a multiplicity of brake cooling fans, at least some of which are arranged for control independently of each other, each such brake cooling fan having an operable mode and an inoperable mode. 
     
     
         7 . An aircraft according to  claim 1 , wherein the mode of operation of the brake cooling fan is set in dependence on the output of a control system. 
     
     
         8 . The aircraft according to  claim 7 , wherein the control system receives an electrical signal from which the frequency of said AC electrical power may be ascertained and said electrical signal is used to determine which mode of operation of the brake cooling fan should be set. 
     
     
         9 . A method of cooling an aircraft wheel brake on an aircraft, wherein the method includes powering a brake cooling fan with AC power from the wild frequency power network on the aircraft whilst ensuring that the frequency of the AC power meets certain criteria. 
     
     
         10 . The method according to  claim 9 , wherein the aircraft includes a multiplicity of brake cooling fans, and the method is performed such that each fan is powered by AC power from the wild frequency power network on the aircraft whilst ensuring that the frequency of the AC power meets certain criteria. 
     
     
         11 . The method according to  claim 10 , wherein the method includes a step of controlling one or more of the brake cooling fans, independently of one or more of the other brake cooling fans. 
     
     
         12 . The method according to  claim 11 , wherein the method includes a step of detecting that one or more of the brake cooling fans, or parts associated therewith, are faulty, and then disabling operation of the one or more of the brake cooling fans independently of other of the brake cooling fans. 
     
     
         13 . The method according to  claim 9 , wherein data received on the aircraft via an electronic data communications network on the aircraft is used to assess whether or not to power the brake cooling fan with AC power from the wild frequency power network 
     
     
         14 . The method according to  claim 9 , wherein the method includes a step of a control system determining whether or not to power the brake cooling fan in dependence on data that is received, such data including data concerning the frequency of the AC power. 
     
     
         15 . An on-aircraft control system configured to control a cooling fan for a landing wheel brake, the control system comprising:
 at least one processor, configured to receive information indicating a frequency of alternating current (AC) power applied to drive the cooling fan, and configured to operate the cooling fan;   a non-transitory memory storing instructions to be processed by the at least one processor, the instructions including:
 determining that the frequency of the AC power exceeds a certain frequency, and 
 issuing a command to disable the cooling fan in response to the determination that the AC power exceeds the certain frequency. 
   
     
     
         16 . A computer program product configured to cause, when the computer program is executed, a programmable control system to form a control system as claimed in  claim 15 . 
     
     
         17 . A kit of parts comprising a computer program product according to  claim 16 , and one or more brake cooling fans.