| 摘要 |
PURPOSE:To shorten exciting time and to prevent quenching due to overshoot, by employing a specific structure in which a superconducting coil is excited using a current whose target value is previously set larger than a desired exciting current value, and when the exciting current value reaches the desired exciting current value, the control command of a lower control means is then switched to the original command. CONSTITUTION:A command generating means 6 generates both the step-like signal A corresponding to the current value which is 2 times as large as the desired exciting current value I0 and the signal B corresponding to the desired exciting current value I0. According to the signal A, a power control means 7 outputs a control voltage signal, and a power source 4 then applies a voltage across a superconducting coil 1. The current through the coil 1 is sensed by means of a current sensing means 5, and a negative feedback loop is so formed as to make the sensed current value to correspond to the signal A, thereby the current through the coil 1 increases rapidly. When the exciting current C through the coil 1 reaches the desired current I0, a comparator 9 outputs a switching signal D. Correspondingly, a switch 10 is made to be connected to a terminal =beta so that the input of the power control means 7 is switched to the original command B, thereby the exciting current through the coil 1 is rapidly decreased to the original command B. |
