Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

In the selection process of low-voltage circuit breakers, the following critical factors must be considered:Rated Current and Short-Circuit Breaking Capacity are fundamental to proper selection. According to relevant standards, the rated current of a circuit breaker should be equal to or greater than the calculated load current, with an additional safety margin (typically 1.1 to 1.25 times). Meanwhile, the short-circuit breaking capacity must exceed the maximum prospective short-circuit current

Alright, folks, Oliver Watts here. Been poking, prodding, and testing these pole-mounted breakers for about eight years now, mostly out in the field but also in the lab. Seen a fair share of good ones, bad ones, and... well, let's just say "interesting" ones. So, when we're talking about signing off on a qualified low-voltage pole-mounted circuit breaker – you know, one that's actually gonna do its job when the sh*t hits the fan out there on the line – it ain't just a quick v

Live-line spraying of PRTV on insulatorsTo ensure the safe operation of transmission lines and effectively prevent pollution flashover, the company's live-line work team recently responded to the local power supply bureau's requirements by conducting live-line spraying of PRTV coating on insulators of relevant transmission lines, equipping the insulators with a bright red "protective coat." The live-line spraying operations were mainly carried out in industrialized towns in central and western C

In modern industrial applications, inverters play a crucial role as key components of electrical drive systems. They enable precise speed control and effectively reduce energy consumption, thereby enhancing the overall efficiency and reliability of the system. This article focuses on the performance evaluation and optimization of inverters in test bench design.As experimental platforms that simulate real-world operating conditions, test benches impose higher performance demands on inverters. The

Surge Arresters: Principles and ApplicationsA surge arrester is a critical device used to protect structures and electrical equipment from lightning strikes. It rapidly diverts and dissipates lightning current, thereby safeguarding equipment and personnel. The following provides a detailed explanation of its working principles.1. Basic Construction of Surge ArrestersA surge arrester typically consists of two main components: a gas discharge tube and a metal oxide varistor (MOV). Gas Discharge Tu

Surge Arresters and Their EvolutionA surge arrester is always connected in parallel with the electrical equipment it protects. It does not interfere with the equipment's normal operation at system voltage. However, when a dangerous overvoltage appears on the equipment, the arrester conducts first, diverting the overvoltage safely into the ground.The earliest and simplest form of surge arrester consisted of two metal rods separated by a gap and connected in parallel across electrical equipment. W

A single-stack variable reluctance stepper motor features a salient-pole stator with concentrated windings mounted directly on the stator poles. The number of phases is determined by the connection configuration of these windings, typically comprising three or four windings. The rotor is constructed from ferromagnetic material and contains no windings.Both the stator and rotor are made of high-quality, high-permeability magnetic materials, requiring only a small exciting current to produce a str

1. Type Test System and StandardsType testing verifies the design rationality and safety of eco-friendly insulated ring main units (RMUs), based on IEC 62271-200 and GB/T 3906, and includes: Insulation Performance: For 12kV RMUs, power frequency withstand voltage is 42kV (1 min) for main circuits and 48kV for breakers. Lightning impulse withstand is 75kV (12kV system) or 125kV (24kV system), with 15 standard impulses (1.2/50μs) per polarity. Partial discharge must be ≤10pC at 1.2&a

Transformer Main ProtectionThe main protection for transformers consists of gas protection and differential protection.Gas ProtectionGas protection is a protective mechanism that responds to internal faults within the transformer tank and to a drop in oil level. When an internal fault occurs in the transformer tank, gases generated from the decomposition of transformer oil and insulation materials due to fault currents and arcing flow from the tank toward the upper part of the oil conservator. T

Main Transformer Backup ProtectionThe purpose of main transformer backup protection is to prevent overcurrent in transformer windings caused by external faults, serve as backup protection for adjacent components (busbars or lines), and, where possible, act as backup for the transformer's primary protection in the event of internal faults. Backup protection is used to isolate faults when primary protection or circuit breakers fail.Main transformer zero-sequence protection is a backup protection f