GB1197535A - Superconductor Generators - Google Patents

Abstract

1,197,535. Superconducting generator. STEMENS A.G. 27 Sept., 1968 [29 Sept., 1967], No. 46165/68. Heading H2A. In a superconducting generator where current is induced in a closed superconducting loop by traversing a plate-like part of the circuit with a confined magnetic field, the strength of the field is varied so that the current flowing in the portion of the plate next to be rendered normal by movement of the field is reduced in magnitude before it is made normal. The strength of the magnetic field is always greater than the critical field of the plate-like part which may be planar or cylindrical and can consist of sheet metal, thin superconductor layers or wires or tapes connected in parallel. In operation, electromagnet 10 is traversed from A-B across wires 1-6 and then is returned to A outside the loop and crosses one of wires 7, 8 which are made of harder superconducting material and connect wires 1-6 to coil 9. As the magnet moves from the position shown to cross-wire 4 it is necessary to reduce the current in wire 4 to near zero and this is done by reducing the strength of the field so that a circulating current is induced in the minor loop defined by wires 3, 4 and the respective parts of wires 7, 8 in a direction to boost the current in wire 3 and buck the current in wire 4. The magnetic field strength is altered by motor-driven potentiometer 14, 13 which varies the excitation current of the magnet and is controlled in accordance with the current flowing in the wire next to be made normal. The current is measured by magnetoresistors 16 which are connected through selector switch 18to the operating coil of relay 15 which controls the current supply to motor 14 and has contacts 20 normally closed. As the excitation decreases so a current is induced in wire 4 in opposition to the existing current thus reducing the magnetic field affecting resistor 16 until its resistance falls sufficiently that relay 15 operates and contacts 20 are opened. When the magnet is returned to point A the excitation current is returned to its initial value. When a superconducting plate is used instead of the wires shown, sensing devices, e.g. Hall plates, are provided along or adjacent to the path of the normal region to measure the current in the superconductor adjacent the normal region. Reference has been directed by the Comptroller to Specification 1,014,527.