Electrical4U 
Introduction of Ammeter An ammeter measures the electric current through a circuit branch. It displays the result in amperes, the SI unit of current. Both the expected current and whether it is AC or DC determine which ammeter and range are suitable. Working Principle of Ammeter The basic principle of an ammeter is to place … Read more
A Foam Fire Protection System is a fire suppression system for hazards approved for its foam concentrate and discharge equipment. A proportioner mixes concentrate with water, then a discharge device aerates the solution to form a foam blanket that suppresses flame and fuel vapour. Back Ground of Foam Fire Protection System Straight water can spread … Read more
Magnetic Circuit A magnetic flux path through a core and any gaps forms a magnetic circuit. The magnetic field is represented by flux lines that close on themselves. A Magnetic Circuit may be driven by a permanent magnet or a coil, while a core made from ferromagnetic materials provides a low-reluctance part of the path. … Read more
Overcurrent protection uses several related settings. The terms used for older induction-disc relays also appear in modern numerical electrical protective relays, but their implementation can differ. The four terms below describe when protective relays pick up and how an inverse-time element determines its operating time: Pick Up Current of Relay In electromechanical electrical relays, a … Read more
Basic Classification of Engineering Materials A basic chemical classification divides Engineering Materials into two broad categories: Metals Metals usually have a crystalline atomic structure, although metallic glasses are amorphous. Most are solid at room temperature, while mercury is liquid. Metals generally conduct heat and have higher electrical conductivity than insulating materials. Many pure metals have … Read more
What is the Rankine Cycle? The Rankine Cycle is a vapor-power cycle used in steam power plants to convert heat into shaft work through steam turbines. Its four basic components are a boiler, turbine, condenser and feed pump. The boiler adds heat at nearly constant pressure. It converts pressurized feedwater into steam at the pressure … Read more
A Lissajous pattern on a Cathode Ray Oscilloscope (CRO) is the X-Y trace of two sinusoids, one on the horizontal plates and one on the vertical plates. The display is a CRT (Cathode Ray Tube). A simple CRT is shown below. Those screen figures are Lissajous patterns. Shape depends on phase difference and on the … Read more
Carnot Cycle The Carnot cycle is a reversible heat-engine cycle between one hot reservoir and one cold reservoir. It has two isothermal legs and two adiabatic (isentropic) legs. No real engine between those two temperatures can beat its thermal efficiency. Carnot thermal efficiency is 1 minus the cold-reservoir absolute temperature divided by the hot-reservoir absolute … Read more
Electrical and electronics engineering materials are the conductors, semiconductors, insulators and magnetic materials used in machines, cables, windings and electronic devices. This page names those four groups and the properties a designer has to specify. Materials science studies composition, structure, processing, properties and performance.For electrical plant that means conductivity, permittivity, dielectric strength, IEC 60085 thermal … Read more
What is Instrument Transformer? An instrument transformer is an AC measuring or protection transformer. It scales a high primary quantity down for measurement of electrical quantities such as voltage, current, power, energy, power factor and frequency. The same cores also feed protection of power system circuits and protective relays. Instrument transformers step AC line voltage … Read more