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Measurements in Open-Channel Turbulence
Published in Michio Sanjou, Turbulence in Open Channels and River Flows, 2022
The electromagnetic velocimetry (EMV) has an intrusive probe, which is an application of Faraday's law of electromagnetic induction. The EMV has been developed over one century, as reviewed by Watral et al. (2015). It composes of an electromagnetic coil for generation of the magnetic field and the electro codes through the induced current flows. When an electro-conductive liquid flows within a pipe where the magnetic field is generated, the electromotive force is induced, which is proportional to the pipe radius, magnetic flux density and the flow velocity. Thus, the flow velocity can be evaluated by the value of the electromotive force.
Electrified Powertrains
Published in Patrick Hossay, Automotive Innovation, 2019
The common form of WPT now used is electromagnetic induction. The basic system functions much like a transformer or even an induction motor, and is a regular feature of many consumer electronics. An electromagnetic coil located in a stationary pad generates a magnetic field that induces a current in a coil on the vehicle. The trick is to achieve good alignment of the coils and closeness. The further the coils are away from each other, the lower the efficiency. Ideally, something in the neighborhood of 4–6 inches would allow a good transfer of power. This is not hard for your cell phone that can be laid directly on a charging pad, but it’s a bit tricky for a car.
Advanced Energy Technologies
Published in Leonard L. Grigsby, and Distribution: The Electric Power Engineering Handbook, 2018
The electricity storage medium is a doughnut-shaped electromagnetic coil of superconducting wire. This coil could be about 1000 m in diameter, installed in a trench, and kept at superconducting temperature by a refrigeration system. Off-peak electricity, converted to direct current (DC), would be fed into this coil and stored for retrieval at any moment. The coil would be kept at a low-temperature superconducting state using liquid helium. The time between charging and discharging could be as little as 20 ms with a round-trip AC–AC efficiency of over 90%.
Maglev weft knitting needle driving modeling and PID controller design
Published in The Journal of The Textile Institute, 2022
Xiaoyan Zuo, Chengjun Zhang, Tao Xiong, Wenshu Yin, Ming Li, Chi Zhang, Xiaoguang Wu, Li Zhu
In order to eliminate the limitation of the friction knitting needle driving, saving the consumption of the knitting machine in processing, and getting the full clothing technology of the weft knitting machine, a innovation maglev weft knitting needle driving model should be built, and maglev knitting needle driving controller should be designed. So, this work intent to build the maglev knitting needle by the equivalent magnetic circuit model, get the accurate displacement in the maglev knitting needle driving processing. The magnetic force of the needle drivng structure is analyzed by the equivalent magnetic circuit model. A PID controller is designed to obtain stable coil voltage, so as to control the magnetic field through the electromagnetic coil voltage. In this way, the needle can be suspended to any position under the action of magnetic force. It supplies technical support for needle driving of circular and flat knitting machines. It also provides an equipment solution for the diversified design of knitting apparel technology in the future.
Adaptive predictive control based on ship magnetic levitation damping device
Published in Journal of the Chinese Institute of Engineers, 2022
Wei-Ran Wang, Jing-Hao Yan, Guan-Jun Yang
As shown in Figure 3, the motion of the float on the x-axis can be decomposed into a rotating motion around the central O point (as shown in Figure 3(a)) and horizontal motion (as shown in Figure 3(b)). The levitation height z, the area S of the equivalent air gap, the mass m and the operating current are fixed values. Based on the above data, the magnetic force that is required to achieve stable levitation can be calculated. Then the relevant data of the required electromagnet can be obtained (Patriawan, Pramujati, and Nurhad 2014; Kawase et al. 2006; Chen et al. 2018). When the suspended object deviates from the equilibrium position, the coil generates electromagnetic force to return the floater to the normal position quickly. When the suspended object returns to the equilibrium position, the electromagnetic force needs to be rapidly reduced. When the levitation magnet is stably floating, the current in the coil is relatively small, so the coil does not need to have a strong current flow capacity. Therefore, enameled wire is used to wind the electromagnetic coil in this paper.
Magnetorheological nanofinishing of BK7 glass for lens manufacturing
Published in Materials and Manufacturing Processes, 2018
Sumit Kumar, Anant Kumar Singh
Because of the flow of direct current in the stationary electromagnetic coil, heat is generated from the electromagnet. A refrigerated bath is used to supply the constant flow of coolant over the electromagnet coil surface through the cooling jacket which continuously dissipated the heat generation from the electromagnet coil. As solid tool core is rotated coaxially inside the electromagnet coil, the heat is transferred from the electromagnet coil to the solid rotating tool core. Therefore, when cooling is applied to the electromagnet coil, the heat may not transfer from the electromagnet coil to the solid rotating tool core. This resulted in maintain of constant low temperature at the solid rotating core tool tip during the finishing operation. Also, due to maintain of constant low temperature, the rheological properties of MR polishing fluid on the tool tip surface cannot be changed as it mainly affected by the rise in temperature.