Notes

How D.C. to A.C. Inverters Work

By Steven McFadyen on 4/22/2014 8:19 AM

Traditionally generation of electricity has involved rotating machines to produce alternating sinusoidal voltage and current (a.c. systems). With the development of power electronics during the last ... read more..

The ac resistance of conductors

By Steven McFadyen on 1/11/2012 11:03 AM

In a previous article I looked at the dc resistance of conductors and in this article we turn our attention to a... read more..

The dc resistance of conductors

By Steven McFadyen on 1/5/2012 9:14 AM

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 this. To get started, this post will look at the... read more..

How to Size Power Cable Duct

By Steven McFadyen on 11/24/2011 5:09 AM

Some colleagues had an issue earlier in the week on sizing conduits to be cast in concrete for some power cables . It became clear that none of us had a clear idea on an approved method. In the end w... read more..

How to Size Current Transformers

By Steven McFadyen on 11/7/2011 6:48 AM

The correct sizing of current transformers is required to ensure satisfactory operation of measuring instruments and protection relays. Several methods exist to size current transformers. This note will... read more..

Back to Basics - Ohm’s Law

By Steven McFadyen on 10/21/2011 9:02 AM

Electrical engineering has a multitude of laws and theorems. It is fair to say the Ohm's Law is one of the more widely known; it not the most known. Developed in 1827 by Georg Ohm the law defines the re... read more..

Alternating Current Circuits

By Steven McFadyen on 4/3/2012 8:29 AM

Alternating current (a.c.) is the backbone of modern electrical power distribution. In this article I’ll be pulling some of the more important concepts together. It is a work in progress and I’ll be add... read more..

Laplace Transform

By Steven McFadyen on 4/23/2012 9:05 AM

Laplace transforms and their inverse are a mathematical technique which allows us to solve differential equations, by primarily using algebraic methods. This simplification in the solving of equat... read more..

UPS Battery Sizing

By Steven McFadyen on 4/8/2012 8:36 AM

Various techniques exist to enable the correct selection of batteries for UPS applications. The procedure described below is one of the more common. It is also possible to use the IEEE 485 method ... read more..

Photovoltaic (PV) - Electrical Calculations

By Steven McFadyen on 7/11/2013 9:46 AM

Photovoltaic (PV) cells (sometimes called solar cells) convert solar energy into electrical energy. Every year more and more PV systems are installed. With this growing application, it's ... read more..

Electromagnetic Compatibility (EMC)

By Steven McFadyen on 7/10/2012 11:23 AM

Electromagnetic compatibility (EMC) is the study of coordinating electromagnetic fields give off equipment, with the withstand (compatibility) of other equipment within the vicinity. In it's simplest... read more..

How a Digital Substation Works

By Steven McFadyen on 3/2/2014 7:06 AM

Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using copper cables. With advances in digital... read more..