| 摘要 |
PURPOSE:To prevent a superconductive coil cooled by immersing in liquid He from quenching by making the coil current fast down when the level of the liquid surface falls abnormally while the coil current is normal or when the coil current is excessively large while the level of the liquid surface is normal. CONSTITUTION:When a relay 53C0 which operates if the coil current is not more than the specified value and a relay 33L1 which operates if the level of the surface of the liquid He falls operate together for more than a specified time continuously, a fast-down relay FD operates according to the signal supplied by an and-circuit AND1, a time-limit relay T1 and an or-circuit OR2. In the same way, if the excessive coil current continues for more than a specified time although the surface of the liquid He is keeping a level more than the specified value, a relay 33L0 and a relay 53C1 operate together and the fast-down relay FD operates the fast-down operation according to the signal supplied by an and-circuit AND2, a time-limit relay T2 and the or-circuit OR2. |
