Conductors For Use Research Articles

Superconductor design and loss analysis for a 20 MJ induction heating coil

The design of a 50 kAmpere conductor for use in a 20 MJ Induction Heating Coil is described. The conductor is a wide flat cable of 36 subcables, each of which contains six Nb-Ti strands around a stainless steel core strand. It is cryostable, with a pool-boiling, fully-normal equivalent heat transfer from the unoccluded strand surface of 0.26 Watts/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . A thin, tough polyester amide-imide insulation enhances heat transfer and prevents interstrand coupling. The tightly-twisted strands are configured using Cu-Ni elements to provide low AC losses with Nb-Ti filaments in an all-copper matrix. AC losses are expected to be approximately: (1) 0.3% of 20 MJ for a -7.5 T to 7.5 T one-second 1/2-cosinusoidal bipolar operation in a 20 MJ coil, and (2) for additional reference, 0.1% of 100 MJ for a 1.8 second -8 T to +8 T ramped operation in a 100 MJ coil with a heat transfer of 0.36 Watts/ cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The design is based on the manufacture and testing of prototype strands and subcables.

Preparation and properties of new oxygen ion conductors for use at low temperatures

Two new systems, Bi 2O 3Er 2O 3 and ZrO 2Y 2O 3(CaO)Bi 2O 3 were investigated. The first system has a homogeneous cubic, fluorite phase between 17.5 and 45.5 mol % Er 2O 3 and can be sintered to densities near 95% at 1200 K. At temperatures between 700 K and 1000 K the highest value of the a.c. oxygen ion conduction in this system is twice as much as the highest value found in the literature. In the second system concentrations of 1–3 mol % Bi 2O 3 act as an excellent sintering aid for ZrO 2Y 2O 3 and ZrO 2CaO samples which can be sintered to densities higher than 95% at temperatures of 1350 K. During this procedure a liquid ZrO 2Bi 2O 3 phase exists from which Bi 2O 3 partly evaporates with increasing sintering time. The oxygen ion conduction is little affected by the Bi 2O 3-rich second phase. The influence of annealing procedures up to 1570 K on the conduction in the ZrO 2Y 2O 3Bi 2O 3 system is small despite weight losses up to 4%.

Superconducting Magnet Materials

Superconducting Magnet Materials

Evaluation of Sodium Conductor Power Cable

The suitability of the newly developed polyethylene- insulated sodium conductor for use in electrical power cables was evaluated electrically and mechanically. Polyethylene-insulated sodium conductors are shown to lend themselves to a wide range of constructions manufactured on standard cable-fabricating equipment. Because of the plastic nature of metallic sodium, neither conductor stranding, nor helical assembly in the case of multi- conductor cables, is required for flexibility.

Trim-coil construction for the Berkeley 88-inch cyclotron

A detailed description of the mechanical construction of the trim coils is presented. It includes selection, optimization and application of a suitable electrical conductor for use under severe radiation conditions, brazing considerations for a very large furnace brazing job, and a discussion of some of the problems encountered during the fabrication procedures.

Copper conductors for overhead lines

Although the title of the paper refers only to copper conductors, copper-alloy and steel-reinforced copper conductors for use on overhead lines are included. The creep of conductors and their initial non-elastic extension are considered in relation to their effect on sags and their compensation by an increase in erection tension as analternative to pre-stressing. A typical stress/strain curve for copper conductors is given.Information on the annealing characteristics of hard-drawn copper and copper-alloy conductors is included, with special reference to the effect of impurities in the metal. Maximum safe operating temperatures for such conductors are discussed, together with maximum permissible current loadings.Hollow copper conductors of various types for voltages up to 200–300 kV are described and some of their characteristics enumerated. The features of cadmium-copper conductors are dealt with in comparison with other types of high-tensile overhead conductor.Steel-reinforced copper conductors receive special attention, particularly in regard to the protection from corrosion of the steel wires. Results of a long-time investigation are given in full, with conclusions and recommendations. Copper-clad steel wires, their characteristics and use as reinforcement in copper conductors, are discussed.Details are given of developments in the application of compressed sleeve joints to copper and copper-alloy conductors. Suitable joints for cadmium-copper and steel-cored copper conductors are described and test results given.