Showing papers by "Evangelos Trifon Laskaris published in 2004"

The Thermal Performance of a 1.5 MVA HTS Generator

Abstract: A 1.5‐MVA high temperature superconducting ( HTS ) generator of novel design has been designed, built and successfully tested by the General Electric Company. The 1.5‐ MVA generator has served as the engineering prototype for a much larger 100‐MVA beta unit now under design.The HTS coil in the 1.5 ‐ MVA demonstrator is designed to operate in the range of 20–40 K and is cooled with a closed‐cycle helium refrigeration system employing GM type cryocoolers. This paper will discuss the calculation of the thermal loads to the rotor from all anticipated sources. These sources include conduction losses through the coil suspension system, radiative heat loads to the cold‐system components, residual gas conduction losses, helium‐transfer coupling losses and lead losses. These predicted losses were compared to those measured during actual electrical testing of the rotor at 3600 RPM in order to validate the predictive calculations employed for the 100 MVA machine.

AC winding with integrated cooling system and method for making the same

Abstract: A winding of an electric machine is provided, where the winding includes at least one series of serially connected AC bars. Each AC bar includes a series of serially connected turns formed by litz wire having a plurality of strands, and at least one cooling tube. Individual strands of the plurality of strands are respectively positioned substantially adjacent to the at least one cooling tube at at least one transfer point for providing heat transfer from the respective individual strands to the at least one cooling tube.

Superconducting multi-pole electrical machine

Abstract: An electrical motor/generator is provided with at least one of a superconducting rotor, a stator including dovetailed winding dividers, and a stator cooling arrangement with at least one cooling tube per winding slot positioned such that each armature winding is thermally coupled to at least one cooling tube.

Multilayer radiation shield

Abstract: A power generation system including: a generator including a rotor including a superconductive rotor coil coupled to a rotatable shaft; a first prime mover drivingly coupled to the rotatable shaft; and a thermal radiation shield, partially surrounding the rotor coil, comprising at least a first sheet and a second sheet spaced apart from the first sheet by centripetal force produced by the rotatable shaft. A thermal radiation shield for a generator comprising a rotor including a super-conductive rotor coil comprising: a first sheet having at least one surface formed from a low emissivity material; and at least one additional sheet having at least one surface formed from a low emissivity material spaced apart from the first sheet by centripetal force produced by the rotatable shaft, wherein each successive sheet is an incrementally greater circumferental arc length and wherein the centripetal force shapes the sheets into a substantially catenary shape.

System and method for cooling a superconducting rotary machine

Abstract: A system for cooling a superconducting rotary machine includes a plurality of sealed siphon tubes disposed in balanced locations around a rotor adjacent to a superconducting coil. Each of the sealed siphon tubes includes a tubular body and a heat transfer medium disposed in the tubular body that undergoes a phase change during operation of the machine to extract heat from the superconducting coil. A siphon heat exchanger is thermally coupled to the siphon tubes for extracting heat from the siphon tubes during operation of the machine.

Quench monitoring and control system and method of operating same

Abstract: A rotating machine comprising a superconductive coil and a temperature sensor operable to provide a signal representative of superconductive coil temperature. The rotating machine may comprise a control system communicatively coupled to the temperature sensor. The control system may be operable to reduce electric current in the superconductive coil when a signal representative of a defined superconducting coil temperature is received from the temperature sensor.

Dynamoelectric machine including superconducting windings

Abstract: A dynamoelectric machine (10) is provided. The machine includes a stator (26) comprising a stationary magnetic core (28), and a plurality of stator windings (32) positioned within said core, said windings electrically coupled to form an electrical circuit, a rotor (12) comprising at least one set of salient pole pieces (22) coupled to a shaft (14), each said set of pole pieces for generating a rotating magnetic field, and a superconducting field coil (40) circumscribing said shaft for generating a magnetic field in each said set of pole pieces.

Permanent magnet assembly with movable permanent body for adjusting main magnetic field

Abstract: PROBLEM TO BE SOLVED: To adjust a B 0 magnetic field for an MRI permanent magnet. SOLUTION: A permanent magnet assembly (11) comprises: a fixed permanent magnet body (15); and movable permanent magnet bodies (22, 26) which are movable relative to the fixed permanent magnet body. A yoke includes: a first part; a second part; and at least one third part for connecting the first part to the second part, so as to form an imaging volume between the first and second parts. The permanent magnet assembly is attached to the first yoke part and includes: the fixed permanent magnet body; and the movable permanent magnet bodies which are movable relative to the fixed permanent magnet body. A magnetic imaging unit therefor is constituted. COPYRIGHT: (C)2005,JPO&NCIPI

System and method for cooling a super-conducting device

Abstract: A system and method for cooling a superconductive rotor coil. The system comprises a rotatable shaft coupled to the superconductive rotor coil. The rotatable shaft may comprise an axial passageway extending through the rotatable shaft and a first passageway extending through a wall of the rotatable shaft to the axial passageway. The axial passageway and the first passageway are operable to convey a cryogenic fluid to the superconductive rotor coil through the wall of the rotatable shaft. A cryogenic transfer coupling may be provided to supply cryogenic fluid to the first passageway.

Parallel wound superconducting coils for a synchronous

Abstract: A superconducting coil assembly includes a plurality of circuit branches. Each circuit branch of the plurality of circuit branches is electrically connected in parallel to each other. Each circuit branch is disposed at a structural core. Each circuit branch of the plurality of circuit branches includes a coil wound from a superconducting wire and a resistive means electrically connected in series to the coil. The coil from each circuit branch forms a plurality of coils with respect to the plurality of circuit branches.

Superconducting wire material, its manufacturing method and article using the same

Abstract: PROBLEM TO BE SOLVED: To manufacture a long (exceeding 500 meters) superconducting wire material (100). SOLUTION: This method for manufacturing the superconducting wire material includes a step of bringing the first end of a first superconducting wire material into contact with the second end of a second superconducting wire material, a step of providing a superconducting filament (110) containing a superconducting composition including a magnesium biboride in the superconducting wire material, a step of heating a point for forming a joint at the first end of the first superconducting wire material to the second end of the second superconducting wire material, and a step of bringing the superconducting filament having the superconducting composition in a continuous electrical contact state with the other arbitrary part of the superconducting filament, after the joint is formed. COPYRIGHT: (C)2005,JPO&NCIPI

Superconducting multipole electric machine

Abstract: PROBLEM TO BE SOLVED: To provide a super conducting multipole electric motor/generator. SOLUTION: The electric motor/generator (10) comprises at least one of a superconducting rotor (100), a stator (200) including dovetail-connected winding split plates (220), and a stator cooling device (300) having at least one cooling pipe (310) per a winding slot (222) arranged so as to be thermally coupled to each armature winding (229). The stator (200) includes at least one cooling pipe (310) per the winding slot (222), each armature winding (229) is thermally coupled to one cooling pipe (310). COPYRIGHT: (C)2005,JPO&NCIPI

Method and apparatus for magnetizing permanent magnet

Abstract: PROBLEM TO BE SOLVED: To provide a magnetizing coil unit and a method of making a magnetizing coil unit. SOLUTION: A coil includes a solenoid coil having a coiled copper sheet in which the width of the copper sheet is equal to the height of the solenoid coil. A magnetizing assembly comprises a plurality of magnetizing coil units, each of the magnetizing coil units comprising a coiled copper sheets placed in a housing, the housing containing a coolant input port in the bottom of the housing, and a coolant output port placed on the upper part of the housing. COPYRIGHT: (C)2005,JPO&NCIPI