Current Issue : October - December Volume : 2019 Issue Number : 4 Articles : 5 Articles
Copper wire is a major conduction material that carries a variety of signals in\nindustry. Presently, automatic wire elongating machines to produce very thin wiresare available for\nmanufacturing. However, the original wires for the elongating process to thin sizes need heating,\ndrawing and then threadingthrough the die molds by the manpower before the machine starts to\nwork. This procedure repeatsuntil the wire threads through all various die molds. To replace the\nmanpower, this paper aims to develop an automatic wire die molds threading system for the wire\nelongation process. Three pneumatic grippers are designed in the proposed system. The first gripper\nis used to clamp the wire. The second gripper fixed in the rotating mechanism is to draw the heated\nwire. The third gripper is used to move the wire for threading through the dies mold. The force\ndesigned for drawing the wire can be adjusted via the gear ratio. The experimental results confirm\nthat the proposed system can accomplish the wiredies mold threading processin term of robustness,\nrapidness and accuracy....
A backstepping-based adaptive controller with neural compensator is designed for harmonic suppression in a three-phase active\npower filter (APF).Thefundamental rule of backsteppingmethod is to take some state variables as â??virtual controlsâ? and then design\nintermediate controller. An adaptive neural controller using radial basis function (RBF) is derived to estimate the APF system\nnonlinearity and strengthen the currentâ??s tracking property and power grid quality. Simulations studies indicate the proposed\nbackstepping-based adaptive neural controller has good current tracking behavior and increased power quality....
The focus of this paper is to propose a contact model of a radial standing wave ultrasonic motor in order to evaluate the motor\nperformance accurately. The contact behavior between the stator and rotor is characterized by test and a continuous contact on\nthe contact interface is confirmed. A contact model describing the continuous contact is then developed with analytical method.\nThe stator vibration, the force transmission between the stator and rotor, and the output of the motor are analyzed.The impacts of\ndifferent vibration amplitudes and structural parameters on the performances of the motor are evaluated based on the proposed\nmodel. Finally, a test platform for measuring the performance of the motor is built and torque-speed curves of the motor under\ndifferent voltages are measured.The accuracy of the contactmodel is verified by comparison between measurement and calculation\nresults. The proposed model not only can be used for design and optimization of the radial standing wave ultrasonic motor but also\noffers insight into the contact mechanics of standing wave ultrasonic motors....
In this paper, the micro-phasor measurement system is developed to support phasor\nidentification of distribution transformers for the distribution mapping management system (DMMS)\nof Taiwan Power Company (TPC). The one pulse per second signal (1PPS) from the global positioning\nsystem (GPS) is used to synchronize the voltage sampling between reference and measurement sides.\nBy receiving 1PPS from GPS, the phasor measurement of three-phase voltage at the reference site\nof the substation is stored in the master station with a time-stamp. This paper proposes a timing\nsynchronous module with an embedded temperature compensated crystal oscillator (TCXO) to\ngenerate highly accurate timing for field measurement of underground distribution facilities. Mobile\ncommunication network is used to compare measurement results between reference and field sides\nof voltage angle that define distribution transformer phasor. This paper also designs and develops an\napplication for mobile devices by importing DMMS database, which is used to search the attributes of\nthe distribution transformers for measurement at the field. After the transformer phasor is identified,\nthe results are stored in the mobile device to update the attributes of distribution transformers\nin DMMS....
Induction motors (IMs) are essential components in industrial applications. These motors\nhave to perform numerous tasks under a wide variety of conditions, which affects performance and\nreliability and gradually brings faults and effciency losses over time. Nowadays, the industrial\nsector demands the necessary integration of smart-sensors to effectively diagnose faults in these\nkinds of motors before faults can occur. One of the most frequent causes of failure in IMs is\nthe degradation of turn insulation in windings. If this anomaly is present, an electric motor can\nkeep working with apparent normality, but factors such as the effciency of energy consumption\nand mechanical reliability may be reduced considerably. Furthermore, if not detected at an early\nstage, this degradation could lead to the breakdown of the insulation system, which could in turn\ncause catastrophic and irreversible failure to the electrical machine. This paper proposes a novel\nmethodology and its application in a smart-sensor to detect and estimate the healthiness of the\nwinding insulation in IMs. This methodology relies on the analysis of the external magnetic field\ncaptured by a coil sensor by applying suitable time-frequency decomposition (TFD) tools. The discrete\nwavelet transform (DWT) is used to decompose the signal into different approximation and detail\ncoeffcients as a pre-processing stage to isolate the studied fault. Then, due to the importance of\ndiagnosing stator winding insulation faults during motor operation at an early stage, this proposal\nintroduces an indicator based on wavelet entropy (WE), a single parameter capable of performing an\neffcient diagnosis. A smart-sensor is able to estimate winding insulation degradation in IMs using\ntwo inexpensive, reliable, and noninvasive primary sensors: a coil sensor and an E-type thermocouple\nsensor. The utility of these sensors is demonstrated through the results obtained from analyzing six\nsimilar IMs with differently induced severity faults....
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