scholarly journals Electromagnetic Field Analysis and Shielding Method of Underground Variable Frequency Power Cable

2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Jianwei Zhang ◽  
Zhuojing Yang
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Waves ◽  
Performance Test ◽  
Electromagnetic Coupling ◽  
Characteristic Impedance ◽  
Test System ◽  
Field Analysis ◽  
Variable Frequency ◽  
Power Cable ◽  
Frequency Power

The transmission and radiation of underground variable frequency electromagnetic waves will seriously interfere with the operation of the power cable and its surrounding environment. At present, the test methods for power cables basically require the impedance of the test system to match the characteristic impedance of the cable. The defect is that the process of designing and making the impedance matching impedance network is relatively complex and requires high manufacturing accuracy. In order to solve these problems, this paper puts forward the electromagnetic field fast detection formula and electromagnetic field shielding method of underground variable frequency power cable. The research method of this paper is the principle of shielding electromagnetic field materials and the suppression principle of shielding layer for electromagnetic coupling. The function of the two principles is to study the reflection, absorption, and multiple reflection of electromagnetic waves and to study the cut-off frequency of the nonmagnetic shielding layer. These two principles guide the experiment. In this paper, the measurement formula of the shielding performance of mismatched cables is derived through experiments. The results show that the error of the measurement formula is no more than 8 dB. Then, through the experiment of restraining the interference of magnetic materials on the electromagnetic field, it is concluded that the magnetic field shielding performance can reach 20 dB. Then, through the performance test of electromagnetic field shielding materials, the shielding efficiency of metal fiber antiradiation materials is the largest, and the average efficiency reaches 76.4 dB.

The Application of Shunt Capacitor in Short-Circuit Test System of Transformer under Variable Frequency Power Supply

2013 ◽  
Vol 392 ◽  
pp. 526-530
Author(s):  
Li Di Wang ◽  
Yue Zhang ◽  
Chun Cheng Han ◽  
Zhe Li
Keyword(s):  
Power Supply ◽  
High Frequency ◽  
Short Circuit ◽  
Engineering Application ◽  
Test System ◽  
Variable Frequency ◽  
Short Circuit Test ◽  
Shunt Capacitors ◽  
Shunt Capacitor ◽  
Frequency Power

The short-circuit test is an important topic on the study of transformer features. With the shunt capacitor paralleled to the tested transformer, the test current can be reduced by the resonant of the capacitor and the inductance of transformer winding. Furthermore, using the high frequency power supply, the capacitor can be reduced in the resonant point because the high frequency values. In this work, the simulation model of short-circuit test of transformer with different frequency power supply is designed. Under variable frequency power supply, which are 50Hz,100Hz and 150Hz, the shunt capacitors value is given. From the simulation results, the application of the shunt capacitor takes a role in the short-circuit test of transformer. This has a significance role in transformer test research and engineering application field.

A High Torque Magnetorheological Brake with Three Effective Areas

2015 ◽  
Vol 742 ◽  
pp. 470-476
Author(s):  
Juan Wang ◽  
Jun Qiang Li ◽  
Zhi Wei Gao
Keyword(s):  
Magnetic Field ◽  
Performance Test ◽  
Mechanical Performance ◽  
Element Model ◽  
Effective Area ◽  
Test System ◽  
Field Analysis ◽  
Performance Simulation ◽  
Magnetic Analysis ◽  
The Magnetic Field

A new structure magnetorheological brake with three effective areas was designed, two end surfaces and the cylindrical surface of the rotor work as effective areas, then the effective area was increased with the same volume of the rotor. Depending on the characteristics of the magnetorheological brake structure, the finite element model of the magnetorheological brake was built, the electromagnetic field analysis was performed, then magnetic field quantities of the brake model were got. With the results of the magnetic analysis and the relation between the yield stress and the magnetic field strength of the magnetorheological fluid, the performance simulation of the magnetorheological brake was realized. On these bases, the magnetorheological brake and the mechanical performance test system were developed, the mechanical performance of the brake was researched used the test system, the brake’s properties: torque vs. speed and yield torque vs. current were obtained.

A High Torque Magnetorheological Brake for Gait Rehabilitation Robot

2015 ◽  
Vol 734 ◽  
pp. 131-137 ◽  
Author(s):  
Juan Wang ◽  
Jun Qiang Li ◽  
Song Song Zhu ◽  
Chao Shi
Keyword(s):  
Magnetic Field ◽  
Performance Test ◽  
Mechanical Performance ◽  
Element Model ◽  
Effective Area ◽  
Test System ◽  
Magnetorheological Damper ◽  
Field Analysis ◽  
Gait Rehabilitation ◽  
Rehabilitation Robot

A new structure magnetorheological brake (MR brake) with three effective areas was designed, two end surfaces and the cylindrical surface of the rotor work as effective areas, then the effective area was increased with the same volume of the rotor. Finite element model of the MR brake was built, the electromagnetic field analysis was performed, then magnetic field quantities of the damper model were got. With the results of the magnetic analysis and the relation between the yield stress and the magnetic field strength of the magnetorheological fluid (MR fluid), the performance simulation of the magnetorheological damper was realized. According to the requirements of the gait rehabilitation robot to the yield torque of the MR brake, the current driver was designed. On these bases, the mechanical performance test system of the MR brake were developed, the mechanical performance of the brake was researched used the test system, the brake’s properties: torque vs. speed and yield torque vs. current were obtained.

Comparison of high- and low-frequency electromagnetic field analysis

1993 ◽  
Vol 3 (3) ◽  
pp. 363-371 ◽  
Author(s):  
A. Konrad ◽  
I. A. Tsukerman
Keyword(s):  
Electromagnetic Field ◽  
Low Frequency ◽  
Field Analysis

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

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