Electrical Lectures
Practical Considerations of Transformer Heat and Noise
In addition to unwanted electrical effects, transformers may also exhibit undesirable physical effects, the most notable being the production of heat and noise. Transformer noise is primarily a nuisance effect, but heat is a potentially serious problem because winding insulation… Read more
Jul 31, 2015 | By Edvard Csanyi
Transformers
Glossary of Power Transformer Terms
There are many terms associated with power and distributive transformers used in electrical networks. These are just some of the most important. Feel free to add any of missing terms in the comment below ;) An Ansi (American National Standard… Read more
Jun 05, 2013 | By Edvard Csanyi
Energy and Power
Rogowski Coil Construction
Figure 1 shows the construction of a Rogowski coil, an air-core current transformer that is especially well suited to measuring ripple currents in the presence of a DC component or measuring pulsed currents. The raw output is proportional to the… Read more
Dec 13, 2012 | By Edvard Csanyi
Energy and Power
Transformer Heat, Copper and Iron Losses
The thermal ratings of a transformer are determined by the following three factors: The amount of heat produced in the windings and connections. The amount of heat produced in the iron core. How effectively the heat can be removed from… Read more
Sep 06, 2012 | By Edvard Csanyi
Transformers
Purpose of Shielded Isolation Transformer
A shielded transformer is a two-winding transformer, usually delta–star connected and serves the following purposes: – Voltage transformation from the distribution voltage to the equipment’s utilization voltage. – Converting a 3-wire input power to a 4-wire output thereby deriving a separate stable… Read more
Aug 29, 2012 | By Edvard Csanyi
Transformers
Power Transformer Construction – Windings
Continued from tech. article: Power Transformer Construction – Core The windings consist of the current-carrying conductors wound around the sections of the core, and these must be properly insulated, supported and cooled to withstand operational and test conditions. The terms winding… Read more
Aug 24, 2012 | By Edvard Csanyi
Electric Motor
Thermal (Overload) Motor Relay Protection
The majority of winding failures in motor are either indirectly or directly caused by overloading (either prolonged or cyclic), operation on unbalanced supply voltage, or single phasing, which all lead through excessive heating to the deterioration of the winding insulation… Read more
Jul 14, 2012 | By Edvard Csanyi
Energy and Power
Autotransformer Connection Explained
An ordinary transformer consists of two windings called primary winding and secondary winding. These two windings are magnetically coupled and electrically isolated. But the transformer in which a part of windings is common to both primary and secondary is called… Read more
Jul 02, 2012 | By Jignesh Parmar
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
Electrical Lectures
Understanding Vector Group of Transformer (Part 1)
Three phase transformer consists of three sets of primary windings, one for each phase, and three sets of secondary windings wound on the same iron core. The vector group of the transformer is determined by the connection between the windings… Read more
Jun 03, 2012 | By Jignesh Parmar
Electric Motor
Measurement of insulation resistance (IR) – Part 2
This article goes into details of insulation resistance values measured by Megger tester on many different kinds of equipment, such as switchgear, electrical wires & cables, electric motors, transmission & distribution lines, and other power system equipment. An insulation tester… Read more
Apr 29, 2012 | By Jignesh Parmar
Protection
Transformer and Transformer-Feeder Protection
The development of modern power systems has been reflected in the advances in transformer design. This has resulted in a wide range of transformers with sizes ranging from a few kVA to several hundred MVA being available for use in… Read more
Nov 30, 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
Energy and Power
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 called autotransformers, shown schematically in figure 1. An autotransformer has… Read more
Aug 19, 2011 | By Edvard Csanyi
Transformers
TRIHAL – Dry type cast resin HV/LV transformer
Trihal is a three-phase dry type transformer cast under vacuum in epoxy resin with an active filler. It is this active filler, essentially composed of trihydrated alumina, which is the origin of the Trihal trademark. The magnetic core is made… Read more
May 22, 2011 | By Edvard Csanyi
