Transformers
Meggering (insulation resistance testing) of dry-type power transformer
The insulation resistance test (meggering) is of value for future comparison and also for determining if the transformer is to be subjected to the applied voltage test.The winding insulation resistance test is a DC high voltage test used to determine… Read more
Jun 27, 2012 | By Edvard Csanyi
Energy and Power
Substation Switching Schemes
This technical article is intended to provide description and comparison of single line options for a DESN substation. The goal is to provide an analytical comparison for all options so that one can select the optimum solution considering cost, reliability,… Read more
Jun 26, 2012 | By Edvard Csanyi
Energy and Power
Commissioning of Electrical Equipment
To verify system condition after has been energized with rated system (service) voltage for which it is designed. Also to ensure the protection, metering system for correct directionality. Multimeter Phase angle meter Phase sequence meter Communication software (if required) Before… Read more
Jun 25, 2012 | By Edvard Csanyi
Electrical Lectures
DC Motor Drive Explained In Few Words
In a DC motor, the magnetic field is created by the current through the field winding in the stator. This field is always at right angles to the field created by the armature winding. This condition, known as field orientation,… Read more
Jun 23, 2012 | By Edvard Csanyi
Transformers
Transformer Extra Losses Due To Harmonics
Non-linear loads, such as power electronic devices, such as variable speed drives on motor systems, computers, UPS systems, TV sets and compact fluorescent lamps, cause harmonic currents on the network. Harmonic voltages are generated in the impedance of the network… Read more
Jun 22, 2012 | By Edvard Csanyi
High Voltage
FACTS – Flexible AC Transmission Systems
The acronym FACTS stands for “flexible AC transmission systems”. These systems add some of the virtues of DC, i.e., phase independence and fast controllability, to AC transmission by means of electronic controllers. Such controllers can be shunt or series connected… Read more
Jun 21, 2012 | By Edvard Csanyi
Energy and Power
Circuit breakers classified by interrupting medium
A circuit breaker is defined as “a mechanical switching device capable of making, carrying and breaking currents under normal circuit conditions and also making, carrying and breaking for a specified time, and breaking currents under specified abnormal circuit conditions such… Read more
Jun 20, 2012 | By Edvard Csanyi
High Voltage
Reducing Distribution Line Losses
One of the main benefits of applying capacitors is that they can reduce distribution line losses. Losses come from current through the resistance of conductors. Some of that current transmits real power, but some flows to supply reactive power. Reactive… Read more
Jun 19, 2012 | By Edvard Csanyi
Transmission and Distribution
Sag and tension of transmission and distribution lines
The energized conductors of transmission and distribution lines must be placed to totally eliminate the possibility of injury to people. Overhead conductors, however, elongate with time, temperature, and tension, thereby changing their original positions after installation. Despite the effects of… Read more
Jun 17, 2012 | By Edvard Csanyi
Electric Motor
Soft Starter In Industrial Applications
An induction motor connected directly to the power supply draws a constant magnetizing current at full speed, no matter what the load is. At anything less than full load, power factor of the induction motor is less than its rated… Read more
Jun 16, 2012 | By Edvard Csanyi
Transformers
ZigZag Transformer Connection Overview
The zigzag connection of tranformer is also called the interconnected star connection. This connection has some of the features of the Y and the ∆ connections, combining the advantages of both. The zigzag transformer contains six coils on three cores…. Read more
Jun 15, 2012 | By Jignesh Parmar
Electrical Lectures
Dielectric Strength Of Insulator Materials
The atoms in insulating materials have very tightly-bound electrons, resisting free electron flow very well. However, insulators cannot resist indefinite amounts of voltage. With enough voltage applied, any insulating material will eventually succumb to the electrical ”pressure” and electron flow… Read more
Jun 14, 2012 | By Edvard Csanyi
Electric Motor
Advantages of Variable Speed Motors
Most motors are designed to operate at a constant speed and provide a constant output. While in many cases this may be more than adequate, it is not in all. Two-speed induction motors can improve efficiency for refrigerators, air conditioners,… Read more
Jun 13, 2012 | By Edvard Csanyi
Transformers
Scott-T Transformer Connection Overview
There are two main reasons for the need to transform from three phases to two phases: to give a supply to an existing two phase system from a three phase supply and to supply two phase furnace transformers from a… Read more
Jun 12, 2012 | By Jignesh Parmar
Transformers
Star-Delta Transformer Connection Overview
In this type of transformer connection, then primary is connected in star fashion while the secondary is connected in delta fashion as shown in the Figure 1 below. The voltages on primary and secondary sides can be represented on the… Read more
Jun 10, 2012 | By Jignesh Parmar
