Equipment for Power Outage in Operation of Driven-Mode NMR Magnet

A 1.02-GHz nuclear magnetic resonance (NMR) system was successfully operated in a driven-mode over a half year. A main coil of the 1.02-GHz NMR magnet consists of a Bi-2223 high-temperature superconducting (HTS) innermost coil and low-temperature s-uperconducting outer coils. The magnet including the HTS coil was designed to operate in the driven mode using highly stabilized dc power supply. The power supply should be operated continuously without interruption. Failure in the power supply due to a power outage is unacceptable. The equipment for a power outage, which consists of an emergency generator, a momentary voltage drop compensator, and a safety switch, was prepared. A malfunction of overcurrent occurred in the momentary voltage drop compensator at the power outage. Due to the equipment for the power outage, the dc power supply was successfully recovered without a quenching of the magnet.