The Influence of Voltage Quality on Asynchronous Motor Performance of EKG Excavator in Open Pit Mines – Vinacomin

At present, in open-pit mining, the main and most important electrical load is the electric excavator, and currently using a variety of EKG excavators. 6kV electrical network in open pit mining has the characteristics such as long outgoing lines, use high-powered equipment, multiple branches, and increasing use of power electronics on the grid, this reduces the quality of the power supplied to the excavators EKG, resulting in an increase in power losses thereby greatly affecting the performance of the excavators. Previous studies on the quality of the power supplied to the excavator often only mentioned voltage deviations, in addition to this factor, the performance of the excavator is also greatly affected by nonsinusoidal voltage waveforms of the excavator power supply. This paper analyzes the influence of the nonsinusoidal of voltage on the power loss of electric motors used in EKG electric excavators in open pit mining based on the method of electromagnetic analysis and verification on simulation software.

IMPATT Diodes Based on 111, 100, and 110 Oriented GaAs: A Comparative Study to Search the Best Orientation for Millimeter-Wave Atmospheric Windows

The authors have carried out the large-signal (L-S) simulation of double-drift region (DDR) impact avalanche transit time (IMPATT) diodes based on 111, 100, and 110 oriented GaAs. A nonsinusoidal voltage excited (NSVE) L-S simulation technique is used to investigate both the static and L-S performance of the above-mentioned devices designed to operate at millimeter-wave (mm-wave) atmospheric window frequencies, such as 35, 94, 140, and 220 GHz. Results show that 111 oriented GaAs diodes are capable of delivering maximum RF power with highest DC to RF conversion efficiency up to 94 GHz; however, the L-S performance of 110 oriented GaAs diodes exceeds their other counterparts while the frequency of operation increases above 94 GHz. The results presented in this paper will be helpful for the future experimentalists to choose the GaAs substrate of appropriate orientation to fabricate DDR GaAs IMPATT diodes at mm-wave frequencies.