scholarly journals The effect of a multi-fracture compression airflow arc-extinguishing structure interrupting the power frequency follow current

AIP Advances ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 035129
Author(s):  
Shangshi Huang ◽  
Jufeng Wang ◽  
Yuheng Xu ◽  
Zijian Li ◽  
Renbao Yan ◽  
...  
Keyword(s):  
Power Frequency ◽  
Fracture Compression

New requirements for power frequency electric field and induced current personal protective equipment

2020 ◽  
Vol 60 (11) ◽  
pp. 849-852
Author(s):  
Sergey Yu. Perov ◽  
Tatyana A. Konshina ◽  
Elena N. Makarova-Zemlyanskaya
Keyword(s):  
Electric Field ◽  
Personal Protective Equipment ◽  
Occupational Safety ◽  
Protective Equipment ◽  
Safety Standards ◽  
Emergency Situations ◽  
Step Voltage ◽  
Power Frequency ◽  
Staff Protection ◽  
Frequency Electric Field

In conditions of exceeding the maximum permissible levels of power frequency electric field, the staff must use personal protective equipment. Requirements for such means are regulated by the system of occupational safety standards. The goal of this work is analyzed new requirements for power frequency and induced personal protective equipment in the regulatory interstate standards GOST 12.4.172 and GOST 12.4.283. The personal protective equipment new requirements for various types of work are substantiated to electrical personnel health safety during the maintenance and operation of power grid facilities. Increasing requirements for personal protective equipment improves the staff protection at ground potential and at wire potential, including in emergency situations such as induced and step voltage.

Study on the "Phase Hopping" AC-AC Frequency Conversion Method with Approximately Continuous Frequencies

2020 ◽  
Vol 13 (8) ◽  
pp. 1217-1226
Author(s):  
Zhengwang Xu ◽  
Guozhuang Jiang ◽  
Ke Kun ◽  
Yuchun Yi
Keyword(s):  
Output Voltage ◽  
Frequency Conversion ◽  
Frequency Control ◽  
Actual Application ◽  
Power Frequency ◽  
Voltage Frequency ◽  
The Law ◽  
Large Cycle ◽  
Selection Of ◽  
Conversion Technology

Background: The output voltage frequency for the previously proposed "phase hopping" AC-AC frequency conversion technology is determined by the law that the number of output voltage cycles is reduced by one relative to the power frequency in a large cycle containing six jumps. According to the law, only a limited number of output frequencies, such as 37.5 Hz, 42.86 Hz and 45 Hz are found. Due to the large spacing between the output frequencies, the "phase hopping" frequency conversion technology is difficult to put into practical use. Methods: In this paper, the law of the output frequency control is generalized so that the number of output cycles in a large cycle is reduced by n relative to the power frequency. The analysis shows that the appropriate selection of large cycles, including the number of power frequency cycles and the value of n, can find more frequencies to be used. Reducing the interval between the output frequencies within 1Hz. Results: The analysis results were verified in simulation by MATLAB, and the harmonics and the feasibility of the actual application were analyzed. Conclusion: Finally, an experimental platform was built and an experimental analysis was carried out. The experimental results show that the theoretical and simulation analyses are correct.

scholarly journals A reconfigurable soft wall-climbing robot actuated by electromagnet

2021 ◽  
Vol 18 (2) ◽  
pp. 172988142199228
Author(s):  
Wendong Zhang ◽  
Wen Zhang ◽  
Zhenguo Sun
Keyword(s):  
Working Conditions ◽  
Horizontal Plane ◽  
Vertical Wall ◽  
Flaw Detection ◽  
Surface Cleaning ◽  
Electromagnetic Actuator ◽  
Climbing Robot ◽  
Soft Wall ◽  
Power Frequency

This article demonstrates a reconfigurable soft wall-climbing robot actuated by electromagnet. The robot follows the earthworm movement gait and is capable of translation, deflection, and rotation movement while working on a sloping ferromagnetic wall. Also the electromagnetic actuator provides a significant improvement in expeditiousness compared with existing actuation modes. The speed of the robot can be adjusted by modulating the power frequency. When the period of motion cycle is 30 ms, the speed is about 26.5 mm s−1, and the robot can rotate with a velocity of 14.1° s−1 on the horizontal plane. It can also climb a vertical wall at the speed of 12.6 mm s−1. The robot is composed of two kinds of modules which can be connected by the magnets embedded. It can also be reconfigured in different working conditions, such as crossing an inaccessible gap, and thus has the potential to be used in flaw detection, surface cleaning, and exploration of ferromagnetic structures.

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