Design of a 100-Kilogauss 4-Inch Core Solenoid for Continuous Operation

Abstract

The design of high field cylindrical solenoid magnets for continuous operation is discussed. Equations are given relating power input, allowable temperature rise, coolant rate, and pressure drop to give the detailed dimensions required for the electrical conductor and the cooling annuli. The stresses from electromagnetic forces acting upon conductors are discussed, equations are given, and some devices and factors concerned in resisting these forces are described. The properties of kerosene as a magnet coolant and safety precautions for its use are discussed. The details for a magnet with a 4‐in. air core, constructed for good homogeneity, and 7.5 megawatts of power are given. A procedure for preparing laminated insulation in the form of a spiral is described and a method of squaring the magnet ends to improve heat transfer, reduce heat production, and facilitate support at the ends has been devised. Equations are given which enable the evaluation of the conductor temperature at any point along the coil by making use of the temperature coefficient of resistance for thermometric purposes. A graph of conductor and kerosene temperatures as a function of axial length has been prepared from data obtained from magnet operation. The particular magnet described here, which is the first of several to be built, gave a field of 99 500 gauss at 7.5 megawatts. Some suggested improvements based on experience with the present magnet have been included.