| 摘要 |
PURPOSE:To enable a device to automatically regulate a neutral point, by regulating the neutral point of operation in a converter to be continually corrected to a proper value in no relation to a change in accordance with a lapse of time, load change of electrode weight or the like and a machining advancing speed in the neutral point. CONSTITUTION:If a switch 16 is closed, an amplifier 14 amplifies a electric potential difference between a reference signal VS and a feedback signal VF, but the amplifier operates as a primary delay circuit because of a capacitor 18 parallelly connected to a resistor 19. Consequently, differential voltage between the reference voltage VS and the feedback signal VF is amplified. The feedback signal VF always changes in accordance with the change of a machining gap, but if a time constant is selected longer than the response period of a follow-up servo, output voltage of the amplifier 14 can be assumed sufficiently as DC voltage with respect to a response frequency of the servo. Accordingly, this output voltage can be assumed as the reference signal in which a change in the neutral point of operation in a servo-valve is automatically corrected. |
