抄録
The research work on manufacturing and testing a superconducting saddle shaped magnet for MHD power generator has been in progress since 1966 at the Electrotechnical Laboratory. So far we have succeeded in making 29cm bore, 2.3 Tesla fully stabilized magnet. It has the following characteristics: Bore diameter 29cm, Outer diameter 76cm, Length 91cm, Number of winding layers 11, Max. central flux density B0=2.3T (at 460Amp) Fully stabilized to at least B0=2.5T (to 500Amp) Max. flux density in magnet windings 3.5T (at 460Amp) Superconductor AVCO SG-500 (4×0.25 in dia. Nb-33% Zr) Weight 1, 120kg
The magnet was precooled to about 48°K in about 16hours by helium gas refrigerator, which supplies the cooled helium gas of 42°K to the dewar in a closed loop. Then liquid helium was poured into the dewar to cool down the magnet to 4.2°K. The magnet has the energy of about 370kJ at the critical current of 460A. The transfer of the magnet energy to the parallel resistor outside the dewar was also successfully tested, that is, about 90% of the magnet energy could be transfered.
