When an alternating magnetic field is applied to a Wiegand wire, a series of pulse voltages are induced in a pickup coil due to fast magnetization reversal known as the large Barkhausen jump. This study aims to analyze the characteristics of the pulse voltage, including its height and area, which are determined from the intensity and frequency of the applied alternating magnetic field. We quantified the energy generated by magnetization reversal in a Wiegand wire. To achieve this, it was necessary to measure the energy consumed by a load resistor connected to the pickup coil. Additionally, we clarified the energy loss in the Wiegand wire.

  In conventional elevators, vibration and twisting of the cable become a serious problem when the cable is long. Therefore, an elevator that omits the counterweight and is moved by an actuator on a single cable with both ends fixed has been considered. However, contact decreases the efficiency and damages the cable owing to the inclusion of foreign matter. Therefore, a vertical transportation system is proposed that moves above a long, uniform conductor cable without contact by using a cylindrical linear induction motor (LIM) as the actuator. A cylindrical LIM above the reaction plate, which is a cylindrical shell-shaped conductor, has the advantage that the magnetic force acts on the reaction plate uniformly. This suppresses the vibration in the gap direction. However, a conventional LIM drives the mover in the horizontal direction. Therefore, a model was constructed for analyzing the cylindrical LIM for vertical transfer, and electromagnetic field analyses were performed using the finite-element method. The thickness of the reaction plate was varied, and the effect on the generated thrust was investigated. The optimal thickness of the cable was determined from the results by obtaining the range of the magnetic flux density acting on the cable.

  To achieve higher performance in spark-ignition engines, the intake and exhaust valves must be controlled in a stepless manner according to the engine speed. Our research group has been continuously studying the electromagnetic drive valve system using a linear actuator. We designed a linear actuator with a dual Halbach array of permanent magnets in the stator to increase the thrust of the linear actuator. The thrust characteristics of the proposed model were investigated using electromagnetic field analysis based on the finite element method. The analysis confirmed that the Halbach array concentrates the magnetic flux on the coil side, which generates Lorentz force. From the analysis results, the proposed liner actuator can generate thrust for driving the engine valve, and optimal permanent magnets in stator can be obtained to generate higher thrust.