Abstract: A superconducting magnet apparatus such as a superconducting magnet for supplying a levitating force to a magnetically levitating train comprises a closed loop-shaped superconducting coil, a container for containing the superconducting coil, a coolant contained in the container, for keeping the superconduction state of the superconducting coil, a metallic member situated outside the container, and path apparatus situated outside the container, for suppressing heat which is generated in the container, the path apparatus having an electric conductivity higher than that of the container and being made of a superconducting wire for causing eddy current occurring outside the container to flow with a small quantity of heat generated.

Abstract: A supervisory system is used for a superconductive transformer which comprises primary to Nth-order windings (N is an integer of not less than 2) windings, and the windings are formed of superconductive lines and are wound around an outer surface of a signal core. The supervisory system can detect quench occurring in the windings. The supervisory system includes N voltage sensors for detecting terminal voltages of the windings of the superconductive transformer, N current sensors for detecting currents of the windings, a magnetic flux detector mounted on the core of the transformer, and a discriminator for discriminating a quenched one of the windings on the basis of change patterns unique to output signals from the voltage sensors, output signals from the current sensors, and an output signal from the magnetic flux detector, and a switch for cutting off supply of an electrical power to the superconductive transformer according to an output signal from the discriminator.

Abstract: A superconducting transformer comprises primary and secondary superconducting coils which are coaxial and made of superconducting wires, and a cryostat for maintaining the superconducting coils in a superconducting state. The cryostat includes a vessel for containing refrigerant and which is formed of a ferromagnetic material. The coils are immersed in the refrigerant. Rod formed of ferromagnetic materials is inserted in the primary and secondary superconducting coils, and is magnetically coupled with the vessel. The cryostat also includes a heat insulating tank for thermally insulating the rod and the vessel from the refrigerant. The rod and the vessel together form a closed magnetic circuit, and function as a core for the superconducting coils.

Abstract: In a monitoring system for detecting a quench in a superconductive coil to which AC power is supplied, a switch apparatus is connected between the coil and a A.C. power source. A voltage between a top of the coil and a dividing resistor connected in parallel with the coil is detected and converted into a voltage signal by a insulation amplifier and a current flowing through the coil 1 is detected by a current detector and is converted into a current signal by an amplifier. The voltage signal is detected with the current signal as a reference signal by a phase detector so that a signal component of the voltage signal in phase with the reference signal is outputted from the phase detector. The signal component is averaged in a averaging circuit, when the voltage signal is out-of-phase with the reference signal, an output signal is generated as an alarm signal from the averaging circuit.

Abstract: A pressure measuring system wherein light is transmitted from a light source via a first optical fiber to a pressure-receiving diaphragm having a reflecting surface which undergoes a deflection in relation to the pressure being measured. The diaphragm reflects light transmitted thereto to a second optical fiber which transmits the reflected light to a first photosensitive element. A reference optical fiber is arranged approximately coextensive to the first and second optical fibers and transmits light from the light source in round trip fashion along substantially the same path as light transmitted by the first and second optical fibers to a second photosensitive element. The photosensitive elements produce respective electrical signals which are applied to an operational circuit which eliminates variations in the amount of light due to external disturbances by dividing one electrical signal by the other.