摘要 |
<p>When a fan drive current has become excessive, a fan drive device intercepts that current, waits for just a fixed time period T1, and thereafter flows that current for a second time. The fan power supply current flowed to the fan drive device is detected by a shunt resistor R. The value of the fan power supply current detected by the shunt resistor R is inputted to a controller, and the cause of any abnormality of the fan is decided upon by this controller, based upon the magnitude of the above described fan power supply current and the time period over which it has continued.</p> |