Application Of High Voltage Test Methods To The Evaluation Of Low Voltage Motor Insulation Quality

AbstractThe electric eel is a unique species that has evolved three electric organs. Since the 1950s, electric eels have generally been assumed to use these three organs to generate two forms of electric organ discharge (EOD): high-voltage EOD for predation and defense and low-voltage EOD for electrolocation and communication. However, why electric eels evolved three electric organs to generate two forms of EOD and how these three organs work together to generate these two forms of EOD have not been clear until now. Here, we present the third form of independent EOD of electric eels: middle-voltage EOD. We suggest that every form of EOD is generated by one electric organ independently and reveal the typical discharge order of the three electric organs. We also discuss hybrid EODs, which are combinations of these three independent EODs. This new finding indicates that the electric eel discharge behavior and physiology and the evolutionary purpose of the three electric organs are more complex than previously assumed. The purpose of the middle-voltage EOD still requires clarification.

Download Full-text

Novel High-Efficiency High Step-Up DC–DC Converter with Soft Switching and Low Component Voltage Stress for Photovoltaic System

Processes ◽

10.3390/pr9071112 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1112

Author(s):

Yu-En Wu ◽

Jyun-Wei Wang

Keyword(s):

High Voltage ◽

Output Voltage ◽

High Efficiency ◽

Low Voltage ◽

Leakage Inductance ◽

Power Switch ◽

Half Wave Voltage ◽

Half Wave ◽

Voltage Stress ◽

Voltage Doubler

This study developed a novel, high-efficiency, high step-up DC–DC converter for photovoltaic (PV) systems. The converter can step-up the low output voltage of PV modules to the voltage level of the inverter and is used to feed into the grid. The converter can achieve a high step-up voltage through its architecture consisting of a three-winding coupled inductor common iron core on the low-voltage side and a half-wave voltage doubler circuit on the high-voltage side. The leakage inductance energy generated by the coupling inductor during the conversion process can be recovered by the capacitor on the low-voltage side to reduce the voltage surge on the power switch, which gives the power switch of the circuit a soft-switching effect. In addition, the half-wave voltage doubler circuit on the high-voltage side can recover the leakage inductance energy of the tertiary side and increase the output voltage. The advantages of the circuit are low loss, high efficiency, high conversion ratio, and low component voltage stress. Finally, a 500-W high step-up converter was experimentally tested to verify the feasibility and practicability of the proposed architecture. The results revealed that the highest efficiency of the circuit is 98%.

Download Full-text

561 Bilateral Upper Extremity Amputation After High Voltage Electrical Injury: A Case Report

Journal of Burn Care & Research ◽

10.1093/jbcr/irab032.211 ◽

2021 ◽

Vol 42 (Supplement_1) ◽

pp. S130-S131

Author(s):

Andrew Khalifa ◽

Anzar Sarfraz ◽

Jacob B Avraham ◽

Ronnie Archie ◽

Matthew Kaminsky ◽

...

Keyword(s):

Case Report ◽

High Voltage ◽

Troponin I ◽

Low Voltage ◽

Foley Catheter ◽

The United States ◽

Upper Extremities ◽

Full Thickness ◽

Electrical Injuries

Abstract Introduction Electrical injuries represent 0.4–3.2% of admissions to burn units and are responsible for >500 deaths per year in the United States. Approximately half occur in the workplace and are the fourth leading cause of work-related-traumatic death. The extent of injury can be drastically underestimated by total body surface area percentage (TBSA). Along with cutaneous burns, high voltage electrical injuries can lead to necrosis of muscle, bone, nervous tissue, and blood vessels. Aggressive management allows for patient survival, but at significant cost. Newer technologic advances help improve functional outcomes. Methods This case-report was conducted via retrospective chart review of the case presented. Results A 43-year-old male sustained a HVEI (>10, 000 V) after contacting an active wire while working as a linesman for an electric company. He presented after less than 15-minute transport from an outside hospital with full thickness burns and auto-amputation to all fingers on both hands and the distal third of the left hand (Images 1 and 2). There were full thickness circumferential burns to the entire left and right upper extremities with contractures, with the burns extending into the axilla, and chest wall musculature. The patient had 4th degree burns and a large wound to the left shoulder with posterior extension to the scapula, flank and back with approximately 25% TBSA (Image 3). Compartments were tense in both upper extremities. Patient was sedated and intubated to protect the airway and placed on mechanical ventilation. A femoral central line was then placed, and the patient was given pain control, continued fluid resuscitation, and blood products. Dark red colored urine from a foley catheter that was immediately identified as rhabdomyolysis induced myoglobinuria. Labs drawn demonstrated elevated troponin I, CK >40,000. BUN 18, creatinine 1.0, K+ 5.2 and phosphate 5.6. Decision was made immediately for operative intervention with emergent amputation of both upper extremities in the light of rhabdomyolysis secondary to tissue necrosis and oliguria. During the patient’s hospital course, he underwent multiple operations for further debridement with vacuum-assisted closure therapy and skin grafting of sites, as well as targeted muscle reinnervation (TMR) 6 months later at an outside hospital. Conclusions Although HVEI only account for a small percentage of burn admissions, they are associated with greater morbidity than low-voltage injuries. Patients with HVEI often incur multiple injuries, more surgical procedures, have higher rates of complications, and more long term psychological and rehabilitative difficulties. Despite the need for amputation in some of these critically ill patients, options exist that allow for them to obtain long term functional success.

Download Full-text