Impact Analysis of PM magnetization level on motor performance: simulations and experimental results

Abstract This paper addresses the impact of magnetization level tolerances in ferrite-based permanent magnets (PM) on the performance of brushless DC motors. A case study is prepared using three motor prototypes assembled with controlled samples of ferrite arc segments, in terms of magnetization. The investigation is performed both experimentally and through simulations using the software SPEED. The results show that narrow tolerance margins for the magnetization conditions in the production line can potentially minimize the use of raw material on such motors whereas keeping the efficiency and torque behavior required by the application

Effect of carbon on magnetocaloric effect of LaFe11.6Si1.4 compounds and on the thermal stability of its hydrides

La(Fe,Si)13 alloys display a giant magnetocaloric effect when a magnetic field is applied near the Curie temperatureT C. However, to use these alloys for domestic refrigeration based on magnetic cooling, it is vital to increase T C near to the room-temperature range while simultaneously maintaining a large magnetocaloric effect. With this aim, we studied the effect of interstitialcarbon on the microstructure and magnetocaloric effect in LaFe11.6Si1.4C x (x = 0–0.4). The investigation was carried out in cast samples annealed for seven days at 1323 K. The study of microstructure shows that annealing led to about 90 wt. % of 1:13 magnetocaloric phase. Magnetization data revealed that the addition of carbon leads to an increase in T C and a decrease of the thermal hysteresis width. For x > 0.2, the magnetic transition changes from first-order to second-order, with a corresponding reduction in magnetocaloric effect. A small amount of C (x up to 0.2) improves the magnetocaloric properties of the parent alloy La(Fe,Si)13, and, furthermore, the carbon addition leads to an increase in the thermal stability of hydrided LaFe11.6Si1.4C x . The onset of hydrogen desorption increases from 460 K for the x = 0 (carbon-free alloy) to 500 K and 540 K, respectively, for x = 0.1 and x = 0.2