Reuse of common elements of a corrector power supply design to develop a dissipative shunt regulator design

The progress in the development of a shunt regulator for the conventional recirculation arc magnets in the CEBAF superconducting recirculating accelerator is described. The shunt is capable of diverting up to 20 A around an individual magnet which is connected in a magnet string energized at a nominal 220 A. The regulation stability goal for the shunted current is 50 PPM. The regulator uses a digital link for both programming and readback of output current. Electrical isolation is achieved by opto-coupling the serial communications link. The circuitry for this regulator was adapted from an existing CEBAF design for corrector magnet power supplies. The reuse of common elements from the corrector supply, especially the isothermal regulator module and the onboard microprocessor, significantly shortened the development time for the shunt regulator