Abstract: A method and apparatus for charging superconducting magnet coils using the Seebeck effect of thermoelectric materials. Superconducting magnet coils are wound from a superconducting material, such as niobium-titanium, and placed in a cryogenic dewar to cool the coil below the critical temperature at which the coil becomes superconducting. The coil can be charged by providing a suitable thermocouple junction outside the dewar and a reference thermocouple junction inside the dewar and connecting the junctions to the coil in a manner providing charging current flow to the coil in accordance with the Seebeck effect. This method is particularly desirable for use with lightweight magnet systems for use in such applications as magnetic levitation systems for trains, space applications, etc. where the present heavy switching power supplies are undesirable.

Abstract: A voltage divider for high voltage vapor cooled leads for superconducting magnet systems. Power connections to large superconducting magnets often carry potentials in the range of 5 to 10 kilovolts. These leads penetrate the cryogenic cooling vessel surrounding the superconducting magnets. In order to avoid excessive heat leak paths that would be caused by conventional electrical insulation, the leads exiting the vessel pass through tubes cooled by boiling helium. Helium gas will break down at any distance in the potential exceeds about 2 kilovolts. Such a breakdown path exists since the vapor cooled lead is at very high potential and the helium source is at ground potential. The voltage divider provides a controlled gradient of the voltage so that no portion of the helium gas sees excessive potentials. The gas at high potential is directed through a series of conductive screens in a tube insulated from each other and connected by a resistive voltage divider.

Abstract: A method of detecting and analyzing normal zones in a superconducting coil which involves generating a signal representative of the real power dissipated within the superconducting coil after the background noise and transient conditions within the coil have been accounted for. The power signal is integrated with respect to time to provide a signal proportional to the total energy dissipated within the superconductor which is then compared against a critical reference signal so that a quench signal is generated to immediately disconnect the superconducting coil when the reference signal is exceeded and to allow the coil to discharge its energy into an external device to prevent coil damage. An exemplary circuit for implementing the method is disclosed.