| 摘要 |
PROBLEM TO BE SOLVED: To surely eliminate a dewing in a casing receiving electrical equipment and to prevent a trouble or malfunction in the electrical equipment by detecting the humidity in the casing by a humidity detecting means, and controlling the current to be supplied to a heater base on the detected humidity. SOLUTION: The electric actuator 1 for driving valve is provided with a reversible electric motor 4 for driving the valve shaft 3 of a butterfly valve or the like, and a control base plate 5 on which an electrical equipment for controlling the electric motor 4 is mounted, within a casing 2. In this case, a humidity sensor is mounted on the control base plate 5 to detect humidity in the casing 2. A humidity signal detected by the humidity sensor is supplied to a humidity monitor function circuit through an A/D converter, hereat the detected humidity is compared with set humidity held in non-volatile memory, and in the case of the detected humidity over the set humidity, a current is carried to a heater 6 provided on the control base plate 5 to raise temperature in the casing 2. |
