Electrical4U 
A quantum is a discrete amount associated with a particular physical mode or transition. Its value can be stated in standard units of energy; one photon at frequency f carries hf. A quantum is not one universal smallest unit of energy: its size depends on the system and frequency. Quantum is singular and quanta is … Read more
A mobile substation is a transportable power distribution system that performs transformation, switching, protection and control functions. Utilities and industrial operators use these units to bypass unavailable equipment, support planned work or make a temporary grid connection. The unit still needs a suitable power source, connection point, site and protection scheme before it can be … Read more
Power transformers connect parts of power systems operating at different voltage levels. Some designs also provide galvanic separation between windings. Installation involves heavy lifting, high-voltage clearances, insulating liquid, stored pressure and complex protection systems, so qualified personnel must work from the approved drawings, risk controls and manufacturer instructions. This article is a planning overview, not … Read more
A residual current circuit breaker (RCCB) disconnects a circuit when the measured residual current meets its operating conditions. It is a residual-current device without integral overcurrent protection. An RCCB can reduce shock and fire risk from certain earth-fault paths, but it does not make contact with live parts safe or replace earthing, insulation and safe isolation. The … Read more
Magnetic saturation is the high-field region in which a ferromagnetic or ferrimagnetic material produces little additional magnetization as the applied magnetic field increases. It is a normal material limit, but a device operating too far into this region may draw excessive current, lose inductance or distort a signal. What is Magnetic Saturation? A magnetic material … Read more
What is a Bimetallic Strip Thermometer? A bimetallic thermometer uses two firmly bonded metal layers with different coefficients of thermal expansion. A temperature change makes the composite strip curve or twist. A mechanical linkage turns that displacement into pointer movement on a calibrated scale. Steel and brass illustrate the principle, but commercial instruments use selected … Read more
Transformer insulating liquid provides electrical insulation and transfers heat in power transformers and other liquid-filled equipment. Transformer oil based on mineral oil also carries dissolved gases and ageing products that can support condition assessment. Oil tests are useful only when the specimen represents the liquid in the equipment. The sampling point, container, flushing method, handling … Read more
Electrical energy is energy transferred or converted by electrical systems. An electric current can deliver energy to a motor, battery, lamp or heater. Electric resistance converts some electrical energy to heat. Power is the rate of energy transfer, while an energy meter accumulates that transfer over time. What is Electrical Energy? Electrical energy over a … Read more
Gas-insulated switchgear (GIS) is metal-enclosed equipment whose insulation relies at least partly on a pressurised gas or gas mixture. Sulphur hexafluoride (SF6) has been widely used, while newer designs also use alternative gases and vacuum interruption. GIS controls part of a power system through enclosed busbars, circuit breakers, disconnectors, earthing switches, instrument transformers and surge … Read more
Radiant flux is the rate at which radiant energy is emitted, transferred or received. Its SI unit is the watt (W), equal to one joule per second. Radiant power is a synonym; optical power is common when the radiation lies in an optical system’s stated spectral range. Radiometry describes optical radiation without weighting it for … Read more