Transient behavior of a magnetorheological brake excited by step currents under compression-shear mode has been experimentally studied. The results show that the amplitude of the applied current had little effect on the rising time of transient torque, while the rising time was significantly affected by the rotational speed, the compressive speed and the compressive strain position. The falling time of transient torque was independent of the amplitude of the applied current, the compressive speed and the compressive strain position, and it was affected by the rotational speed. The falling time of the transient torque was much shorter than the rising time by a step current. The transient process of MR brake applied as a step current was different from a stable process pre-applied at constant current in different particle chain structure forming processes. In addition, the compressive processes applied in one step current and randomly on/off current were compared and experimentally verified: the particle chains in two processes both experienced the same evolutionary of transient torque. The results achieved in this study should be properly considered in the design and control of magnetorheological brake under compression-shear mode.
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http://dx.doi.org/10.1038/s41598-021-91836-6 | DOI Listing |
Sensors (Basel)
January 2025
Departamento de Ingeniería Electrónica, Universidad de Sevilla, 41092 Seville, Spain.
Variable-speed electrical drive control typically relies upon a two-loop scheme, one for torque/speed and another for stator current control. In modern drive control methods, the actual mechanical speed is needed for both loops. In practical applications, the speed is often acquired by incremental rotary encoders.
View Article and Find Full Text PDFISA Trans
December 2024
Dept. of Electrical Engineering, Jadavpur Univerity, Kolkata, India. Electronic address:
Due to robustness and low-cost, Induction motors are among the most commonly utilized types of motors in industrial applications. The operation and efficiency of any induction motor can be predicted with reasonable accuracy by solving its equivalent circuit. However, the equivalent circuit parameters may differ from the measured one with aging and when the operating conditions varies.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Rheology describes the flow of fluids from food and plastics, to coatings, adhesives, and 3D printing inks, and is commonly denoted by viscosity alone as a simplification. While viscometers adequately probe Newtonian (constant) viscosity, most fluids have complex viscosity, requiring tests over multiple shear rates, and transient measurements. As a result, rheometers are typically large, expensive, and require additional infrastructure (e.
View Article and Find Full Text PDFJ Hum Kinet
October 2024
Graduate School of Sport and Exercise Sciences, Osaka University of Health and Sport Sciences, Sennan, Osaka, Japan.
The effects of jump exercises as a conditioning activity (CA) on the rate of force development (RFD) measured during the isometric midthigh pull (IMTP) have not been investigated. Therefore, we aimed to investigate the effect of the CA comprising three sets of five countermovement jumps on the RFD measured during the IMTP, and furthermore to investigate whether post-activity potentiation (PAP) would be involved in this mechanism. Thirteen healthy male university students (age: 19.
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October 2024
Department of Electrical/Electronics and Computer Engineering, Afe Babalola University, Ado-Ekiti, Nigeria.
Multiphase machines are very essential for industrial applications that require high reliability of operation. In this paper, a comparative study of three-phase and five-phase inverter fed permanent magnet synchronous motors (PMSMs) was evaluated with respect to their performance characteristics under a healthy state and during transient disturbances such as varied load and double line to ground faults. To avert inherent high oscillations in speed and torque ripples during fault condition, the machine load was significantly reduced to 1/4th of the full load and a post fault current limiting series dynamic braking resistance (SDBR) with a bypassed switch was introduced to enhance the machine fault tolerant level and improve its operational performance.
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