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EMI Measurements, Control Requirements, and Test Methods
Published in David A. Weston, Electromagnetic Compatibility, 2017
A modified conducted emission test setup that may be utilized at a user’s installation using the voltage probe is shown in Figure 9.14. A voltage probe may also be used where the use of a LISN is impossible due to high current requirements of the EUT. In the test setup with the voltage probe, both the EUT and the installation environment are tested. The problem with the test method is that AC power-line conducted noise from locations outside of the jurisdiction of the user are also measured. The addition of a large ferrite balun with 2–10 turns on all the power conductors, including safety ground, can help reduce the ambient noise. An alternative test method that is not approved by the FCC but that has a number of advantages over Figure 9.14 is shown in Figure 9.15. One advantage of the test circuit compared to the LISN is that it may be easily constructed. The inductor may be wound on a metal oxide or ferrite toroid, and the 10-µF capacitor should, where feasible, be an RF feedthrough type. By the choice of a large enough metal oxide toroid, a current capacity of up to 200 amps may be achieved. The second advantage of the proposed setup is that the current probe measurement is isolated from power-line-generated noise by the series inductor. The test circuit can provide an impedance within the tolerance limits of Figure 9.13. Although the proposed setup is useful in diagnostic and precertification measurements, only an FCC-type LISN or the line probe, at the user’s site, is likely to be accepted by the FCC for certification purposes.
Capacitors, Inductors, and Duality
Published in Nassir H. Sabah, Circuit Analysis with PSpice, 2017
A simple expression for the inductance of the coil in Figure 7.15 can be readily derived, based on two simplifying assumptions: (1) that the current-carrying wire is tightly wound around the core and that the wire diameter and thickness of insulation around the wire are sufficiently small so that the flux outside the core is negligible; in other words, all of the coil flux is confined to the core, and (2) that the diameter of the core is small compared with the mean diameter, a, of the toroid, so that H can be assumed constant across the transverse cross section of the core. It follows from Equation 7.19 that H = NI/πa, independently of r. From Equation 7.14, B = μH, where μ = μrμ0 (Equation 7.14). Hence, B=μπaNI
The Electromagnetic Phenomena as Incitants
Published in William J. Rea, Kalpana D. Patel, Air Pollution and the Electromagnetic Phenomena as Incitants, 2018
William J. Rea, Kalpana D. Patel
In mathematics, a toroid is a doughnut-shaped object, such as an O-ring (Figure 2.8). It is a ring form of a solenoid. Its annular shape is generated by revolving a plane geometrical figure about an axis external to that figure that is parallel to the plane of the figure and does not intersect the figure (Figure 2.8). When a rectangle is rotated around an axis parallel to one of its edges, then a hollow cylinder (resembling a piece of straight pipe) is produced. The toroid is a surface generated by rotating a closed curve about an axis that is in the same place as the curve that does not intersect it.
Milky translucent haze of a large-scale topological defect array in nematic liquid crystal
Published in Liquid Crystals, 2023
where is the index of a surface defect. Above the circular electrode, a defect with topological charge () of +1 is generated. The projected field on the substrate plane is a two-dimensional (2D) radial point defect with of +1. Ideally, the defect tends to sit at the centre of the circular electrode to have static balance, but the defect can easily drift away from the centre and then attach to a dust or a bump [18]. In the cylindrical annulus (toroid) boundary created by the annulus electrode, the defects with topological charge of +1 and −1 appear in pairs. Sometimes the positive-negative pairs simply annihilate. Since the annulus electrode does not have fine strips or pattered surface pretilt treatment to control the in-plane field, the defect can appear on any location.
A new non-isolated interleaved high step-up gain DC-DC converter with reduced voltage stress on switching devices
Published in International Journal of Electronics, 2022
Meghna A. Vaghela, Mahmadasraf A. Mulla
The cost of proposed topology and compared topologies is calculated for rating of 24 V input, 380 V output, output power of 300 W, fsw = 50 kHz and n = 1. The cost of semiconductor devices and capacitor is considered from mouser website. Core of CIs for each topology is considered KDM sendust toroid core. The proposed topology has to operate at D = 0.5 and topology 1 has to operate at D = 0.55 so that IPP051N15N5 (150 V) MOSFET is considered. Topologies 2, 3, 5 and 6 have to operate at D = 0.621 so that IPP110N20NAXK (200 V) MOSFET is considered. Topologies 4 and 7 have to operate at D = 0.75 so that IRF300P226 (300 V) MOSFET is considered. The diode rating is considered twice the calculated value. Cost of control circuit, winding of CIs and PCB are not considered. It can be seen in Table 1, the proposed converter, topology 1 and topology 7 has same cost and lowest in compared topologies for same rating design. Maximum efficiency of proposed topology and compared topologies is mentioned at different load conditions.
An efficient algorithm for calculating the cutter location point based on projection method
Published in International Journal of Production Research, 2018
Xiaolin Xi, Yonglin Cai, Fenglei Zhang, Heng Wang
Tool path planning has intimate relationship with the shape of cutter, and ball-end tool is a common cutter used in surface machining (Cai and Zhao 2014). In order to acquire larger liner velocity during the cutting, cutters with large diameter and high-speed rotation are usually used in the freeform surface processing, such as toroid cutters (Cai, Zhao, and Wang 2013). Toroid cutter is a torus which is formed by a circle blade, with radius r, rotating around the centre of tool L, as it is shown in Figure 1(a) and (b) is structure of torus. In the literature, several articles deal with the CL point calculation with toroid cutters, such as five-axis strip width maximisation machining (Ni et al. 2001), Hermite method (Engeli, Waldvogel, and Schnider 2002), multi-point machining method (Warkentin 2004) and rotary contact method (Fan, Li, and Cai 2011) etc. In the use of projection method with toroid cutter, Peng et al. (2008) proposed an algorithm of quickly calculating the shortest distance between cutter and surface according to the feature of surface to obtain CL point. Cai et al. (2013) presented a tool path planning algorithm using the similarity relation between adjacent CL points and CC points with toroid cutter under helix driving mode.