Patent ID: 8190396

Claim:
A failure diagnosis system for cooling fans, comprising: a first cooling device having a first cooling fan; a second cooling device having a second cooling fan; and a control device executing a first failure diagnosis which checks the failure of said second cooling fan based on the rotation rate of said second cooling fan at a first time at which the rotation rate of said first cooling fan is reduced or stopped, wherein after said first failure diagnosis, said control device executes a second failure diagnosis which checks the failure of said first cooling fan based on the rotation rate of said first cooling fan at a second time at which the rotation rate of said second cooling fan is reduced, said control device issues a monitoring instruction for said first failure diagnosis and said second failure diagnosis to said first and second cooling devices to monitor at a predetermined timing, said first cooling device further comprises: a first monitoring unit monitoring the rotation rate of said first cooling fan, and a first memory unit in which a first threshold value information of the rotation rate is stored, said second cooling device further comprises: a second monitoring unit monitoring the rotation rate of said second cooling fan, and a second memory unit in which a second threshold value information of the rotation rate is stored, in response to said monitoring instruction said first and second monitoring units check the normality of the rotation rate of said first cooling fan and said second cooling fan, respectively, based on said first and second threshold value information, and each send an error signal to said control device when the rotation rate is not normal, said first memory unit has a third threshold value information of the rotation rate, said second memory unit has a fourth threshold value information of the rotation rate, said first and second monitoring units check the normality of the rotation rate of said first and second cooling fan, respectively, based on said third and fourth threshold value information at a predetermined timing, and each execute a periodic diagnosis in which said error signal is sent to said control device when the rotation rate is not normal, a first monitoring unit starts to execute, before said first failure diagnosis, a first mask processing which masks said error signal which is to be detected in said periodic diagnosis and stops said first mask processing after said first failure diagnosis, and a second monitoring unit starts to execute, before said second failure diagnosis, a second mask processing which masks said error signal which is to be detected in said periodic diagnosis and stops said second mask processing after said second failure diagnosis.