| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a countermeasure against an instantaneous voltage drop of a servo amplifier using a small, reliable and inexpensive device. <P>SOLUTION: A DC voltage terminal 16 of an instantaneous voltage drop protective device 1 is connected to a PN terminal 36 of a servo amplifier 3. In normal operation, a DC voltage supplied from the PN terminal 36 is boosted by a bidirectional DC/DC converter 12, and an auxiliary charge part 16 stores electric energy in an electrolytic capacitor 11. When a voltage detected with an input/output voltage detecting part 21 drops to or below a predetermined threshold value upon occurrence of the instantaneous voltage drop, a control part 25 turns off a switch 14 while switches the bidirectional DC/DC converter 12 to a step-down mode. A DC voltage from the electric energy held in the electrolytic capacitor 11 is stepped down and is supplied to the servo amplifier 3 through the PN terminal 36. Since switching is performed for DC, no phase matching is required, resulting in a simplified circuit. Since charging is made at a high voltage, a large electric energy can be held even if the capacitance of a capacitor is relatively low. <P>COPYRIGHT: (C)2010,JPO&INPIT |
