| 摘要 |
<p>For the purpose of preventing generation of burning or disconnection of an inrush current preventing resistor (3) when making and breaking of an AC power supply are frequently repeated, energy to be charged to a smoothing capacitor (4) at the time of making the power supply is calculated from the capacitance of the smoothing capacitor (4) of a capacitor-input type rectifying circuit and the value of a rectifying smoothing DC voltage, and a mean power is calculated from the energy and the number of times of power making and breaking within a predetermined period of time. If the mean power exceeds an allowable power of the inrush current preventing resistor (3) for preventing an inrush current at the time of making the power supply, warning by an alarm display or an alarm output and power non-making interlock are carried out, and driving of a load-side device is stopped. In the case where the capacitance of the smoothing capacitor (4) and the value of the rectifying smoothing DC voltage are known in advance, the number of power on/off times within a predetermined period of time is counted. If the number of times exceeds a predetermined number, warning by an alarm display or an alarm output and power non-making interlock are carried out, and driving of the load-side device is stopped. <IMAGE></p> |
