Alternating Current Circuits

By Steven McFadyen on 4/3/2012 1:29 PM

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 2:05 PM

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 1:36 PM

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..


Electromagnetic Compatibility (EMC)

By Steven McFadyen on 7/10/2012 4:23 PM

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..


A mechanical engineering paper, some history and memories

By Steven McFadyen on 2/27/2014 12:38 PM

I was digging in my bookshelf and came across the 80th Anniversary Association of Mine Resident Engineers, Papers and Discussions Commemorative Edition (May 2004). Within it's dark covers, is a paper I ... read more..


Network Theory – Introduction and Review

By Steven McFadyen on 5/16/2012 6:02 PM

In electrical engineering, Network Theory is the study of how to solve circuit problems. By analyzing circuits, the engineer looks to determine the various voltages can currents with exist within the... read more..


Capacitor Theory

By Steven McFadyen on 6/12/2013 1:52 PM

Capacitors are widely used in electrical engineering for functions such as energy storage, power factor correction, voltage compensation and many others.  Capacitance is also inherent in any ele... read more..


What is Aircraft Ground Power

By Steven McFadyen on 4/11/2013 12:53 PM

Ever wondered what kind of power an aircraft uses when parked at the airport stand.

Normally the aircraft generates it own power, but when parked with the engines switched off power provided ... read more..


Battery Sizing

By Steven McFadyen on 4/8/2012 1:34 PM

This article gives an introduction to IEEE 485 method for the selection and calculation of battery capacity.

read more..


Voltage Levels – Confused?

By Steven McFadyen on 3/23/2009 2:06 AM

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..


IEC Reference Designations

By Steven McFadyen on 8/26/2009 11:55 PM

The IEC publishes a series of documents and rules governing the preparation of documents, drawings and the referencing of equipment.   Depending on country and industry, people are either f... read more..


Useful Motor Technical Information

By Steven McFadyen on 3/28/2012 10:09 PM

Sometimes it’s useful to be able to quickly lookup a piece of technical information.  This note is a collection of information related to motors, and in particular ac induction motors. read more..




Meeting room of the future

The IET site has a video of a visit showing of a high tech meeting room developed at Napier University in Edinburgh. It a good demonstration of innovative...

Induction Motor Equivalent Circuit

Induction motors are frequently used in both industrial and domestic applications.  Within the induction motor, an electrical current in the rotor is induced...

Electromechanical Relays

Electromechanical relays have been the traditional backbone of electrical protection systems.  While over recent years these have been replaced by microprocessor...

UPS Sizing - Rules of Thumb

It wasn't so long ago I was telling someone that I don't use rules of thumb as most things are easily calculated anyhow.   As it turns out I last week...

Voltage Levels to IEC 60038

The standard aims to consolidate AC and traction voltages within the industry and defines the following bands: band 1 - A.C. systems 100 V to 1...

How a Digital Substation Works

Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using...

Lithium Ion Battery

Over recent years the Lithium Ion battery has become popular in applications requiring high power densities with small weight and footprint.  Today Lithium...

Generation of a Sine Wave

A fundamental concept behind the operation of alternating current systems is that voltage and current waveforms will be sinusoidal – a Sine Wave. This...

EU Code of Conduct on Data Centres - Best Practices

The European Union is implementing a voluntary code of practice for participants with the aim of improving the overall efficiency of data centres. As part...

Star-Delta Motor Starting - Performance

Many questions sent in to the site are in connection with motor starting and in particular star-delta.  For all but the simplest application, there is...

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