From the monthly archives: May 2012

We are pleased to present below all posts archived in 'May 2012'. If you still can't find what you are looking for, try using the search box.

Periodic Electrical Installation Inspection – How Often?

By Steven McFadyen on 4/26/2012 12:08 PM

How often installations are inspected is up to the owner of the installation, provided such durations do not exceed any regulatory maximums in force. The criticality of the electrical installation to th... 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..


Are We Losing Professional Integrity

By Steven McFadyen on 4/20/2012 12:04 PM

I have been thinking recently that there appears to be less professional integrity around than when I first started my career in electrical engineering. Recently the IET has also had a discussion around... read more..


Three Phase Power Simplified

By Steven McFadyen on 4/17/2012 2:00 PM

A single phase system is perhaps the most common type of system most people are familiar with. This is what people have in their homes and what appliances are plugged in to. For larger amounts of power,... read more..


Generation of a Sine Wave

By Steven McFadyen on 4/16/2012 1:57 PM

A fundamental concept behind the operation of alternating current systems is that voltage and current waveforms will be sinusoidal – a Sine Wave. This is best explained by considering how a coil of wire... read more..


Low Voltage Circuit Breakers

By Steven McFadyen on 4/15/2012 1:55 PM

Circuit breakers are switching devices whose primary function is to isolate parts of an electrical distribution system in the even of abnormal conditions.  Abnormal conditions are generally caused ... read more..


Post Authorship

By Steven McFadyen on 4/15/2012 1:53 PM

In 2011, with the introduction of it’s Panda search ranking algorithms, Google introduced tools for determining the original author of posts.  The intention is to provide more relevant search... read more..


Lighting Design - An Introduction

By Steven McFadyen on 4/12/2012 1:50 PM

From the earliest times, humans have found ways to create light. Pre-historic peoples used natural materials (moss, grass, etc.) soaked in animal fat and then ignited. Around 3000 to 4500 BC, oil lam... read more..


International System of Units (SI System)

By Steven McFadyen on 4/9/2012 1:47 PM

The International System of Units (abbreviated SI) is the world's most widely used system of units.  The system consists of a set of units and prefixes. read more..


Standard Cable & Wire Sizes

By Steven McFadyen on 4/9/2012 7:45 AM

IEC 60228 is the International Electrotechnical Commission's international standard on conductors of insulated cables. Among other things, it defines a set of standard wire cross-sections. In the United... read more..


Equipment Verification (to IEC Standards)

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

One of the requirements to ensuring that everything works is to have equipment selected, manufactured and verified [tested] to IEC standards. Not all equipment out there meets this requirements. It is t... read more..


Batteries

By Steven McFadyen on 4/8/2012 1:38 PM

A battery consists of one or more cells, each of which use stored chemical energy to produce electrical energy, There are many types of cells and these are combined in a multitude of ways to produce ... read more..


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Cable Sizing Software

When sizing cables nearly, everyone uses some form of software. This ranges from homespun spreadsheets to complex network analyses software. Each has its...

MIT OpenCourseWare

MIT OpenCourseWare, makes the materials used in teaching all MIT subjects available on the Web, free of charge, to any user in the world.

Electromagnetic Fields - Exposure Limits

Exposure to time varying magnetic fields, from power frequencies to the gigahertz range can have harmful consequences.  A lot of research has been conducted...

Control Theory

Control theory looks at how systems work and are controlled from a mathematical view.  This note gives a brief introduction to some of the concepts – more...

Questions - Reputation and Privilege

Our question and answer system while letting you do exactly what it says, is much more.  It is a dynamic user driven system, where our users not only ask...

Gas Insulated or Air Insulated Switchgear

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...

Medium Voltage Switchgear Room Design Guide

Many medium voltage (MV) indoor switchgear rooms  exist worldwide. The complexity of these rooms varies considerably depending on location, function and...

RLC Circuit, Resistor Power Loss - some Modelica experiments

Modelica is an open source (free) software language for modelling complex systems. Having never used it before, I thought I would download a development...

Lightning Risk Assessment (IEC 62305)

IEC 62305 'Protection against lightning' requires a risk assessment be carried out to determine the characteristics of any lightning protection system...

Wiki Depreciation

We have had the Wiki with us for a long time now, but at last I have decided to say bye bye – more details on why below.

Have some knowledge to share

If you have some expert knowledge or experience, why not consider sharing this with our community.  

By writing an electrical note, you will be educating our users and at the same time promoting your expertise within the engineering community.

To get started and understand our policy, you can read our How to Write an Electrical Note