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.

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..


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..


Introduction to Lighting

By Steven McFadyen on 4/4/2012 1:32 PM

When looking at the design of a lighting scheme it is useful to have an understanding on the nature of light itself and some of the basic theory associated with this.  This article provides an over... read more..


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..


Electromechanical Relays

By Steven McFadyen on 4/2/2012 10:21 PM

Electromechanical relays have been the traditional backbone of electrical protection systems.  While over recent years these have been replaced by microprocessor based numerical devices, there are ... read more..


Understanding electric motor insulation & temperature

By Steven McFadyen on 4/2/2012 3:01 PM

Anyone specifying or using electric motors should have a basic understanding how the insulation is related to temperature. Three classes of insulation are in common use (with 'F' being the most common).... read more..


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What happened to the cable notes?

If you are wondering what happened to our cable notes, the short answer is that we have moved them to myCableEngineering.com.  The "Knowledge Base" at...

How to Size Current Transformers

The correct sizing of current transformers is required to ensure satisfactory operation of measuring instruments and protection relays. Several methods...

How to measure power supply quality

If your are ever called out to troubleshoot something on your electrical system, one of the first things consider is the supply voltage. You want to ensure...

Three Phase Current - Simple Calculation

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...

Introduction to Traction Substations

Following on from my post on railway electrification voltages, I thought an introduction to traction substations would be a good idea. Traction substations...

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...

Load Flow Study – how they work

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...

Voltage Levels – Confused?

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...

110 or 230 Volts

I've been considering a blog on the 110 or 230 Volt issue for a while.  While browsing the Internet I came across a great summary by Borat over at  engineering...

Fault Calculation - Per Unit System

Per unit fault calculations is a method whereby system impedances and quantities are normalised across different voltage levels to a common base.  By removing...

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