PROTECTION SYSTEM FOR SUPERCONDUCTIVE WINDING OF MAGNETIC CIRCUIT

摘要

A protection system for a superconductive winding of a magnetic circuit, in which an additional device (7) for control of a superconductive switch (5) is inductively connected to the main superconductive winding (3) of the magnetic circuit. The superconductive winding (3) of the magnetic circuit is shunted by a discharge resistance (9) which is connected in parallel to the main winding (3) and to the superconductive switch (5). The discharge resistance may be located either outside the cryostat (1) or inside its vaporisation section, thus allowing to economize the heat carrier, or may be in the heat connection with the superconductive winding or may consist of a noninductive winding. The main control device (6) is provided with an independent power source. The additional control device (7) is inductionally connected to the main winding (3) of the superconductive magnetic circuit by means of an introduced secondary winding (8) inductionally connected to the main one which may consist of a superconductive wire. The current from the power source is directed to the main winding (3), the superconductive switch being in its normal position. When the desired level of the current is reached the operator switches off the main control device (6) consisting, for example, of a heater, and the superconductive switch (5) is set into the superconductive state. The secondary winding turns the superconductive switch into the normal position if the normal zone is established in the main winding when the current in it drops by less than 1 %. A part of the accumulated energy is then released on the discharge resistance and the maximum temperature of heating of the superconductive winding is lowered, thus increasing the reliability of the system. The increase of the current density allows to make the system cheaper.