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

1. Selection of Test InstrumentsThe main test instruments for microcomputer protection devices are: microcomputer relay protection tester, three-phase current generator, and multimeter. For testing high-voltage microcomputer protection devices, it is recommended to use a microcomputer relay protection tester capable of simultaneously outputting three-phase voltage and three-phase current, and equipped with timing function for digital inputs. For testing low-voltage microcomputer protection devic

I. BackgroundWith the advancement of intelligent power systems, microcomputer protection devices have become core components in modern industrial power distribution systems due to their high precision, multifunctionality, and reliability. Taking the power distribution project of a natural gas recovery station in the Middle East as a case study, this paper explores the critical role of AM series microcomputer protection devices in enhancing system safety, reliability, and automation levels, and a

1.Selection and Role of Microcomputer Integrated Protection Devices1.1 Selection of Microcomputer Integrated Protection DevicesTo ensure a microcomputer integrated protection device correctly and accurately performs its relay protection tasks, selection during design should comprehensively consider reliability, response time, maintenance and commissioning, and additional functions.Signal input for microcomputer integrated protection devices is the same as traditional relay protection: voltage an

Operating Conditions for Transformers The installation site must be free from flooding, located at an altitude not exceeding 1,000 meters, and maintained in an ambient temperature not exceeding 40°C. Relative humidity may reach 100% within an operating temperature range of 40°C to -25°C (on-load tap changers and temperature controllers must be rated for -25°C). The installation area should be clean, free from conductive dust and corrosive gases, and equipped with sufficient natural or mechanical

Heidrich Pouring Tank Features a fully integrated online film degassing system for enhanced resin quality. Employs static mixing technology—ensuring contamination-free processing with zero waste. Offers programmable mixing ratios and adjustable pouring speed for precise process control. Achieves an internal vacuum level of 0.8 to 2.5 bar, optimizing resin penetration and impregnation.Horizontal and Vertical Cutting Lines Delivers high-precision machining with a tolerance of ±0.01 mm and burr con

Compared to traditional oil-filled transformers, dry-type transformers offer several advantages. Key benefits of dry-type transformers include:Safety: Dry-type transformers are considered safer as they lack flammable liquid insulation (such as oil). They eliminate risks associated with oil leaks, spills, and related fire hazards. This makes them suitable for indoor installations, especially in areas where fire safety is a priority, such as commercial buildings, hospitals, and schools.Environment

Accurate time relay measurement requires systematic steps to ensure reliable results. Before measurement, confirm the relay model, rated parameters, and operating environment, maintaining ambient temperature at 20±5°C and humidity below 85%RH. Prepare a high-precision timer (resolution 0.001s), regulated power supply (±1% fluctuation), standard load (matching contact rating), and digital multimeter.Calibrate the timer and power supply, ensuring equipment error is within ±0.5%. Mount the relay on

Operating Conditions in National Standard GB 6450-1986Ambient temperature: Maximum ambient temperature: +40°C Daily average maximum temperature: +30°C Annual average maximum temperature: +20°C Minimum temperature: -30°C (outdoor); -5°C (indoor) Horizontal axis: Product load; Vertical axis: Average coil temperature rise in Kelvin (note: not in Celsius).For Class H insulation products, the long-term temperature resistance of insulation materials is stipulated by the state as 180°C. However, the in

In electrical control systems, AC contactors are among the commonly used electrical components, and they are also a common source of various electrical faults. After long-term use—especially in harsh environments with high levels of dust—AC contactors may sometimes emit squeaking or rattling noises after being pulled in and held. The causes of this phenomenon are analyzed as follows.Squeaking Noise After Pull-In and HoldingA fully functional AC contactor makes no noise when energized and pulled

AC contactors (with the electrical schematic code KM) are core electrical devices used to control the connection/disconnection between power supplies and loads in circuits, and they are also common equipment that electricians need to work with regularly. In practice, it is not uncommon to find that some peers make mistakes in selecting AC contactors, leading to improper sizing and subsequent persistent issues. Here, four of the most typical common mistakes are highlighted for reference.I. Over-R