We are pleased to present below all posts archived in 'April 2009'. If you still can't find what you are looking for, try using the search box.
Using software in our work is essential for most of us and we are becoming even more dependant on it's use. While software is a great asset, many times using it can be more problematic ... read more..
I was having a conversation the other day about voltage levels. While everyone was in agreement that low voltage was 1000 V and less, there was more confusion on the terms 'Medium Voltage' and ... read more..
American inventor Thomas Alva Edison was born in Milan, Ohio on February 11, 1847. He was the youngest of seven children and received little formal schooling. Most of his education happened at home unde... read more..
The other day I was reading 'Night of the New Magicians' by Mary Pope Osborn with my son. The story is about a young boy and girl who travel back in time to the 1889 World's Fair in Paris to find ... read more..
The calculation of current in a three phase system has been brought up on our site feedback and is a discussion I seem to get involved in every now and again. While some colleagues prefer to remember... read more..
The new standard IEC 61439 replaces the old 60439. Compared to the old standard, the new 61439 is a more clearly defined and takes into account the assembly...
Various arguments exist around SF6 Gas Insulated (GIS) and Air Insulated (AIS) medium voltage switchgear. Recently we had to change a GIS design to AI...
This morning I was explaining how differential protection works to a junior engineer. To give him something to read I opened up the NPAG (Network Protection...
This is the first of two posts on the resistance of conductors. In the next post I will look at the ac resistance, including skin effect and we deal with...
The windings of many medium and small sized transformers are protected by restricted earth fault (REF) systems. The illustration shows the principal of...
Three phase systems are derived from three separate windings, either connected in delta or star (wye). Each winding can be treated separately, leading...
Estimating maximum demand is a topic frequently discussed. Working out how much power to allow for a building can be very subjective . Allowing too much...
In an earlier note on the site [Photovoltaic (PV) - Electrical Calculations], the theory of solar (PV) cell calculations was introduced. In particular...
Years ago I was told that you should always try to write the best report you can. Many years later I still think on this as one of the better pieces of...
A load flow study is the analysis of an electrical network carried out by an electrical engineer. The purpose is to understand how power flows around...
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