Electric actuator

摘要

A most recent electrostatic capacitance value for a backup capacitor is measured periodically. Each time the most recent electrostatic capacitance value is measured, a charging voltage (a required charging voltage) that is required in order to cause a return operation of a valve from the setting opening at that time to an emergency opening/closing position (for example, the fully closed position) is calculated based on the electrostatic capacitance value that has been measured, and the terminal voltage of the backup capacitor is adjusted so as to become equal to the calculated required charging voltage.

主权项

1. An electric actuator comprising a motor receiving a supply of electric power from a power supply portion and driving a valve, and a backup capacitor that is charged through the receipt of electric power from the power supply, performing a return operation, at the time of a power outage, on the valve to a prescribed opening position through forcibly driving the motor through electrical energy that is stored in the backup capacitor, comprising:
an electrostatic capacitance measuring unit measuring periodically a most recent electrostatic capacitance value for the backup capacitor; and a charging voltage calculating and adjusting unit calculating, as a required charging voltage, a charging voltage for the backup capacitor that is required in order to cause the return operation of the valve from the opening setting value at that time to the prescribed opening position, based on the measured most recent electrostatic capacitance value, each time the most recent electrostatic capacitance value of the backup capacitor is measured and adjusting the terminal voltage of the backup capacitor so as to become equal to the calculated required charging voltage.