Improved Torque Magnetometer

Abstract

A new automatic recording torque magenetometer has been designed and constructed. This instrument will automatically plot the torque exerted on a thin ferromagnetic disk slowly rotating in a uniform magnetic field as a function of the angle between a reference direction in the disk and the direction of the applied field. The torque exerted on the disk is converted into a dc electrical signal. Conversion is accomplished by coupling the mechanical torque system to a strain gauge transducer whose electrical output is used to drive a dc strip chart recorder. This type of torque magnetometer was first designed by D. S. Miller. Emphasis is placed on various design features of the new magnetometer that are considered improvements over the original. In particular improvements have been made on the bearings, shaft, and strip which constitute the important features of the instrument. Depending on the transducer that is used, the measurable torque range is 0 to 70×103 ergs. The sensitivity of the highest range is approximately 2×103 ergs/mv.