Papers by Keyword: Equivalent Circuit

Abstract: This study aimed to present a method for measuring the mechanical strength and electrical chargeretention properties of fibers containing nano-sized oxide particles, which have become widely usedin recent years, and to clarify the fundamental physical properties of these fibers. There have beenfew studies measuring the mechanical and electrical properties of composite fibers containing nanosizedoxide particles. Polyester fibers containing SiO2 and ZrO2 nanoparticles were fabricated usingindustrial techniques to clarify the effect of particle introduction on strength. Furthermore, theelectrostatic charge properties of fibers containing these particles, which act as insulators, weremeasured, revealing that mechanical strength and electrical charge retention properties are mutuallyexclusive parameters. Increasing the nanoparticle content decreased mechanical strength, butprolonged the charge half-life and improved electrostatic retention. Furthermore, it was shown thatthis phenomenon can be represented using an equivalent circuit model of a resistor and a capacitor.

Abstract: This paper proposes a method for estimating the equivalent circuit parameters of an induction motor from manufacturer’s datasheet information using the Gröbner basis algorithm. Induction motor parameters are crucial for motor control and performance monitoring, yet they are often not readily available from manufacturers. To address this issue, an approach is developed that minimizes the normalized error between the computed performance of the equivalent circuit and the manufacturer’s specifications. The Gröbner basis algorithm is implemented in MATLAB to facilitate parameter estimation. The method is tested on 5 hp, 50 hp, and 500 hp sample motors and the results are compared with Genetic Algorithm and Newton-Raphson methods. Findings show that the Gröbner basis approach achieves comparable accuracy to these established methods, with percentage errors generally below 7% for key parameters like rotor resistance, stator resistance, and leakage impedance. Notably, the Gröbner basis method requires no iterations, overcoming the slow convergence issues associated with the other techniques. This study demonstrates that the Gröbner basis algorithm offers an effective, non-iterative solution for estimating induction motor parameters with moderate accuracy, providing a valuable alternative to conventional approaches.

Abstract: Gel phantoms are useful materials for medical diagnostics and impact testing. The gel phantoms can be tailored to suit various tissues from the bulk, microscopic and molecular components. These components have responses under an AC electric field. In this work, a gel phantom was prepared using a commercially-available gel powder. Cylindrical samples with varying degrees of defects were cut from the prepared gel phantom and tested using an AC impedance analyzer. The defects were created by piercing a needle along the center plane of the sample and the degree of defects was varied by increasing the number of piercings in the sample. The conductivity of the sample at lower frequencies was influenced by the mechanism involved in water leakage due to piercing while the conductivity at higher frequencies was dominantly affected by space charge relaxation and structural conductivity barriers. The Nyquist plots obtained were seen to exhibit modified Randles-type behavior. Equivalent circuit fittings showed the parameters to be distinct with varying degrees of defects.

Abstract: Electric impedance is widely used in imaging and detection techniques. The applications range from non-destructive testing, structural health monitoring, and geophysical imaging to medical imaging. The frequency of the signal used for the measurement ranges from less than 1 Hz to about 1 GHz. This paper addresses the measurement and evaluation of the phase dependent electrical resistance, inductance, capacitance, and impedance of a shape memory alloy (SMA) spring (BMX 150, Toki Corporation). The material characteristics can be obtained by means of their electromechanical impedance. Experimental procedures are implemented and the electrical characteristics are obtained for a wide range of frequency. The electrical resistance, inductance, impedances of the austenite and martensite phase are determined, also the quality factor of the Bio Metal coil to be (9.465 – 9.95) Ω and (10.358 – 10.8) Ω, (0.458 – 0.38) μH and (0.458 – 0.36) μH and, (9.47 – 10.24) Ω and (10.36 – 11.11) Ω respectively for the frequency range of 100 kHz - 1MHz. The quality factor of the Bio Metal ranges between 0.03 and 0.2 during heating and, 0.028 and 0.022 during the cooling phase. The experimental results herein show that an equivalent circuit of the SMA spring is a series resistor-inductor circuit with a parasitic capacitance effect. The electromagnetic behaviour of SMA is determined using a finite element tool.

Abstract: Dielectric relaxation and conductivity of Ni_0.3Zn_0.7Fe₂O₄ (NZF) were studied in the frequency range between 0.01 Hz to 3 MHz and temperature range within 313 K to 473 K. The sample was prepared by mixing Zinc Oxide, Nickel Oxide and Iron Oxide and sintered at 1573 K for 10 hours long. Dielectric properties were studied using Novo Control Dielectric Spectrometer. Dielectric relaxation and conductivity phenomena were discussed using an empirical model to key out the dielectric relaxation process. Analyze peak frequency relaxation process consist of four slopes to explain the dielectric relaxation process. The conductivity of the sample indicates an activated process and activation energy of dc conductivity is 0.44 ± 0.01 eV.

Abstract: In this article the method which allows us to perform the calculation of the electromagnetic field in an electrical motor jointly with the calculation of current in a coil and with the rotor rotation under the effect of electromagnetic forces and loads is considered. The possibilities of this method application to the electrical motor design are demonstrated with several tasks. The comparison with the experimental data obtained for the asynchronous motor with two squirrel-cage windings of the rotor is given.

Abstract: A thermal mathematical model of the induction traction motor was developed. The thermal model calculates the motor node temperatures with minimum number of input parameters. It can be applied as a thermal control condition system of electric traction motors during the operation. The adequacy testing results of the mathematical model in ELCUT were presented. Also, the comparison of mathematical model information and the results of experimental researches were submitted.

Abstract: The article considers the problems of the mathematical modeling of thermal physics of the tool for nanostructuring burnishing. Physical and equivalent heat diagram of the system are developed. On the basis of the equivalent heat transfer diagram, the equivalent circuit and the system of equations of the mathematical model are created. The dependence of the tool indenter tip temperature on cooling system thermal parameters is obtained. The comparison of efficiency of heat removal from the tool indenter when using the developed two-circuit cooling system and the system supplying lubricant cooling liquid through the lathe centre spindle, as well as when applying nanostructuring burnishing without cooling is carried out.

Abstract: A thin-disc ultrasonic actuator using a piezoelectric buzzer is proposed as the actuating component for the shaft-driving type ultrasonic actuator. By placed the screw constraints on the metal sheet of a buzzer, a 3-phase reflected wave was constituted and propagated based on the purpose locations of constraints. This wave configuration could convert electrical energy to actuate the kinematical power for rotating the rotor. The input and output signals were acquisition according to the single-frequency exciting of system resonant frequency. The dynamic transfer function of a stator was obtained via the system identification technique, and, therefore, one model of a 3^th-order equivalent circuit was built in which the dynamic features and electromechanical characteristics were considered based on material oscillating behaviors. Because of the admittance transfer function derived from measured method, it is more representative than that of past issues through the theoretical deduction in materials, physics, and mechanics.

Abstract: EIS technique was employed to study corrosion of the rusted cast iron artifacts in seawater. The impedance spectra show characteristic of diffusion in the complex plane. At low frequencies, the complex impedance data trace out straight lines with less slopes with increasing immersion time. Equivalent circuit provides useful information that the rusted iron undergoes severe corrosion in seawater in the presence of porous scale. SEM results reveal the morphologies of the three main iron oxyhydroxides.