| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost apparatus for diagnosing failures in a fan motor. SOLUTION: The failure-diagnosing apparatus comprises a fuse that is connected in series with the fan motor, a voltage deciding circuit for detecting the winding short-circuiting of the fan motor or the locking of a rotor by detecting the voltage in the connection point between the fuse and the fan motor, a resistor having a large temperature coefficient that is mounted and fixed to a section for detecting the temperature increase in the fan motor, and a resistance judgment circuit for detecting the disconnection of the winding of the fan motor, by detecting the change in the resistance of the resistor for detecting temperature. A thermistor, for which a resistance value decreases as temperature increases, is used for the resistor for detecting temperature. The resistance deciding circuit detects the disconnection of the winding in the fan motor according to the difference between the resistance of the resistor for detecting the temperature, before the fan motor starts operating and a resistance value, when temperature is saturated in specific time after the fan motor starts operating. Especially, the fan motor is the one that is provided in the freezer of a chill car. |
