DESIGN AND PRELIMINARY TEST-RESULTS OF THE 40 MW POWER-SUPPLY AT THE NATIONAL-HIGH-MAGNETIC-FIELD-LABORATORY

Four highly stabilized, steady-state, 10 MW power supplies have been i nstalled at the National High Magnetic Field Laboratory in Tallahassee , FL. Each supply consists of a 12.5 kV vacuum circuit breaker, two th ree-winding, step-down transformers, a 24-pulse rectifier with interph ase reactors and freewheeling diodes, and a passive and an active filt er. Two different transformer tap settings allow dc supply output volt ages of 400 and 500 V. The rated current of a supply is 17 kA and each supply has a one hour overload capability of 20 kA. The power supply output bus system, including a reversing, switch at the input and 2 x 16 disconnect switches at the output, connects each supply to 16 diffe rent magnet cells. The design of the power supply is described and pre liminary test results with a supply feeding a 10 MW resistive load are presented.