| 摘要 |
PROBLEM TO BE SOLVED: To provide a spring return motor actuator which can maintain the temperature rise of a drive coil of the motor to a constant value, suppress burning of drive coil, and keep a valve open for a long period of time. SOLUTION: A power supply G and a thermistor P having positive characteristics are located in series to the drive coil MA of motor M, and a fixed resistor or capacitor R is connected in parallel to the thermistor P having positive characteristics. Under the predetermined temperature of the drive coil, the resistance of the thermistor having positive characteristics is set smaller than the resistance of the fixed resistor or capacitor, and the resistance value of the thermistor having positive characteristics is set larger than the resistance of the fixed resistor or capacitor under the temperature higher than predetermined. |
