Autotransformers in few words
It is possible to obtain transformer action by means of a single coil, provided that there is a “tap connection” somewhere along the winding. Transformers having only one winding are… Read more
Aug 19, 2011 | Edvard
Applications and forms of differential relays
Differential relays take a variety of forms, depending on the equipment they protect. The definition of such a relay is “one that operates when the vector difference of two or… Read more
Aug 15, 2011 | Edvard
Whole-House Protection Strategy
No single SPD (Surge Protection Strategy) can protect all the equipment in a residence from all causes of electrical surges. Instead, a whole-house protection strategy, consisting of point-of-entry and point-of-use… Read more
Aug 13, 2011 | Edvard
Principles for Controlling Harmonics
Harmonic distortion is caused by nonlinear devices in the power system. A nonlinear device is one in which the current is not proportional to the applied voltage. Harmonic distortion is… Read more
Aug 05, 2011 | Edvard
DC to AC Transfer – Measurement
General transfer capability is essential to the measurement of voltage, current, power, and energy. The standard cell, the unit of voltage which it preserves, and the unit of current derived… Read more
Jul 30, 2011 | Edvard
Resistive heating explained in details
Whenever an electric current flows through a material that has some resistance (i.e., anything but a superconductor), it creates heat. This resistive heating is the result of “friction,” as created… Read more
Jul 27, 2011 | Edvard
Materials with magnetic properties
All materials have magnetic properties. These characteristic properties may be divided into five groups as follows: Diamagnetic Paramagnetic Ferromagnetic Antiferromagnetic Ferrimagnetic Only ferromagnetic and ferrimagnetic materials have properties which are… Read more
Jul 26, 2011 | Edvard
Fire Protection Measures
The measures to mitigate or lessen fire hazards are normally called “fire protection measures”. The National Fire Protection Association NFPA (U.S. organization charged with creating and maintaining minimum standards and… Read more
Jul 13, 2011 | Edvard
Fuses – Principles of design and operation
A fuse consists of a replaceable part (the fuselink) and a fuse holder. Examples of fuse holders are shown in Fig. 1. The simplest fuselink is a length of wire…. Read more
Jul 09, 2011 | Edvard
Area classification in potentially explosive atmospheres
Area classification defines hazardous areas on the basis of the probability of a flammable atmosphere being present. It is a legal requirement under DSEAR for any employer whose business involves… Read more
Jul 08, 2011 | Edvard
Generator tripping as stability control
Generator tripping is an effective (cost-effective) control especially if hydro units are used. Tripping of fossil units, especially gas- or oil-fired units, may be attractive if tripping to house load… Read more
Jul 06, 2011 | Edvard
Designing Raw DC Power Supplies
Every type of electrical or electronic apparatus needs a source of electrical energy to function. The source of electrical energy is called the power supply. The two main classifications of… Read more
Jul 03, 2011 | Sa'ad Eddin
Fuel cells in power section
In 1839, a British Jurist and an amateur physicist named William Grove first discovered the principle of the fuel cell. Grove utilized four large cells, each containing hydrogen and oxygen,… Read more
Jul 01, 2011 | Edvard
Who was James Prescott Joule?
James Prescott Joule was born on Christmas Eve 1818 into a wealthy Salford brewing family. A sickly child, he was tutored at home where he indulged his fascination for electricity… Read more
Jun 27, 2011 | Edvard
Thumbs down to the nuclear energy
Although for decades the arguments against nuclear power have been –and still are- strong and valid, there is an increasing group of nuclear companies supported by scientists and politicians, who… Read more
Jun 15, 2011 | Edvard
