Transformers
Sources of Sound in Transformers
Unlike cooling-fan or pump noise, the sound radiated from a transformer is tonal in nature, consisting of even harmonics of the power frequency. It is generally recognized that the predominant source of transformer noise is the core. The low frequency,… Read more
Nov 09, 2011 | By Edvard Csanyi
Energy and Power
Working Principle of Earth Leakage Circuit Breaker (ELCB) and Residual Current Device (RCD)
The operation of an earth leakage circuit breaker (or shorten ELCB) is based on the fact that the algebraic sum of the currents in any healthy single phase, three phase and three phase and neutral system is zero. This simply… Read more
Nov 07, 2011 | By Jignesh Parmar
Electric Motor
DC motor and generator – design, application and operation
History will recognize the vital role played by DC motors in the development of industrial power transmission systems, the dc machine being the first practical device to convert electrical power into mechanical power. Inherently straight forward operating characteristics, flexible performance… Read more
Nov 06, 2011 | By Edvard Csanyi
Biomass Energy
Biodiesel – Myths and Facts
Few facts you most probably know already, but never the less to mention: A clean burning alternative fuel, produced from domestic, renewable resources such as plant oils, animal fats, used cooking oil and even new sources such as algae. Contains… Read more
Nov 05, 2011 | By Bipul Raman
Lighting
Basic parameters used in lighting you should know
Abbreviation: φ phi Unit: lm lumen The luminous flux describes the quantity of light emitted by a light source. The luminous efficiency is the ratio of the luminous flux to the electrical power consumed (lm/W). It is a measure of… Read more
Nov 03, 2011 | By Edvard Csanyi
Protection
Transformer Winding Faults
A fault on a transformer winding is controlled in magnitude by the following factors: Source impedance Neutral earthing impedance Transformer leakage reactance Fault voltage Winding connection Several distinct cases arise and are examined below. The winding earth fault current depends… Read more
Nov 02, 2011 | By Edvard Csanyi
Maintenance
Retro perspective 30 years ago: Metal-Clad or Metal-Enclosed MV Switchgear? What to choose?
There are two types of switchgear commonly applied today for switching and protection of in-plant medium voltage (4.16 kV through 34.5 kV) power distribution systems. One is metal-clad switchgear using draw-out air-magnetic or vacuum circuit breakers and relays for both load… Read more
Oct 31, 2011 | By Edvard Csanyi
Energy and Power
The Importance of the Correct PPE
Whilst awareness of the dangers of arc flash has continued to increase over the last few years, the number of incidents that are still occurring on a daily basis are shockingly high. Arc flash incidents are the greatest threat to… Read more
Oct 29, 2011 | By cgoulds
Transformers
Transformer Testing Techniques
Cant see this video? Click here to watch it on Youtube. Substation transformers can range from the size of a garbage can to the size of a small house; they can be equipped with a wide array of gauges, bushings,… Read more
Oct 27, 2011 | By Edvard Csanyi
Electronics
Power Semiconductor Device – Transistor
Power transistors are used in applications ranging from a few to several hundred kilowatts and switching frequencies up to about 10 kHz. Power transistors used in power conversion applications are generally npn type. The power transistor is turned on by… Read more
Oct 27, 2011 | By Edvard Csanyi
Electrical Lectures
What is the difference between MCB, MCCB, ELCB, and RCCB
This technical article briefly describes the most common breaker-related protection devices in low-voltage applications: MCB, MCCB, ELCB, and RCCB. We’ll describe their main characteristics and limitations and try to solve some misunderstandings and differences that many young engineers mix up…. Read more
Oct 25, 2011 | By Jignesh Parmar
Protection
Short circuit protection of generator’s stator windings by overcurrent relays
If current transformers are not connected in the neutral ends of wye-connected generator windings, or if only the outgoing leads are brought out, protective devices can be actuated, as in Figure 1, only by the short-circuit current supplied by the… Read more
Oct 24, 2011 | By Edvard Csanyi
Low Voltage
How Low-Voltage Air Circuit Breaker Works?
A low-voltage circuit breaker is one which is suited for circuits rated at 600 volts or lower. One of the most commonly used low-voltage air circuit breakers is the molded case circuit breaker (picture above). A circuit can be connected… Read more
Oct 23, 2011 | By Edvard Csanyi
Transformers
Forced ventilation cycles in Trihal transformers
Transformers, when in operation, are subject to no-load losses and load losses. This energy causes a rise in the temperature of the transformer’s active part, i.e. the magnetic core and the windings. It is therefore normal for the transformer to… Read more
Oct 22, 2011 | By Edvard Csanyi
Electronics
Insulated-Gate Bipolar Transistor (IGBT)
The IGBT has the high input impedance and high-speed characteristics of a MOSFET with the conductivity characteristic (low saturation voltage) of a bipolar transistor. The IGBT is turned on by applying a positive voltage between the gate and emitter and,… Read more
Oct 21, 2011 | By Edvard Csanyi
