| 摘要 |
<p>PURPOSE:To enable the stable and highly-precise detection of a change in a high-speed large current, by providing a compensating amplifier which supplies a compensation signal to a feedback amplifier when a current signal of a current detector exceeds a reference value. CONSTITUTION:A magnetic amplifier is constituted of magnetic bands 1A-1D of a saturable reactor, conductors 2A-2D to be measured and output windings 3A-3D. When a current I1 to be measured flows through the conductors 2A-2D to be measured, a current proportional thereto is going to flow to output resistances 62, 72 of current detecting elements 6, 7. Then an output voltage makes a current flow to feedback windings 4A-4D through a feedback amplifier 1, and the current stops at a point whereat it becomes equal to the ampere-turn of the current of the conductors to be measured. At this time, the current to be measured can be detected from the voltage across an output resistance 4E. In the case when the current to be measured becomes large transiently, on the other hand, compensating amplifiers 8, 9 output compensation signals S1, S2. Therefore an output of the feedback amplifier 1 conducts no negative action even in a state wherein a positive feedback action is to be conducted, and thus control stability becomes excellent.</p> |
