| 摘要 |
PURPOSE:To prevent a trouble due to thermal OFF-tracking, etc., by providing a converter for converting noise generated from a cooling fan into an electric signal and an abnormal-noise detector circuit. CONSTITUTION:Noise 2 generated from a cooling fan 1 is always monitored so that the change of an electric signal from a converter 3 is detected by an abnormal-noise detector circuit 4 and sent as an alarm signal to an interface 5. Said interface circuit 5 receives the alarm signal and sends an alarm to an external apparatus 6. Thus, when said cooling fan 1 varies in said noise 2 due to deterioration, etc., said alarm is sent to the external apparatus 6. Therefore, before the number of revolutions of the cooling fan 1 lowers, it is possible to detect the deterioration of said cooling fan 1 in an early stage and to exchange the cooling fan 1. Thus, it is possible to prevent a trouble by thermal OFF tracking, etc. |
