From the monthly archives: November 2014

We are pleased to present below all posts archived in 'November 2014'. If you still can't find what you are looking for, try using the search box.

Tips for a better Low Voltage Protection Discrimination Study

By Steven McFadyen on 11/3/2014 11:48 AM

Carrying out a protection system discrimination study is critical to ensure the correct functioning of  the electrical system in the event of faults.  The IEC defines discrimination as:

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Back to Basics - Ohm’s Law

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...

The dc resistance of conductors

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...

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...

Bows and Arrows

It starts with me reading one of the Horrible History books with my son (Groovy Greeks). Arrows were mentioned which lead to the discussion of the bodkin...

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...

DC Component of Asymmetrical Faults

The image (reproduced from IEC 60909) shows a typical fault in an ac system.  From the illustration it can seen that there is an initial dc component ...

Power Transformers - An Introduction

One of the fundamental requirements of an alternating current distribution systems it to have the ability to change the magnitude of voltages.  It is more...

Railway Electrification Voltages

This post is quick introduction and overview to different railway electrification voltages used in answer to a question sent in via email. While there...

Motor Efficiency Classification

Electric motors are one of the most widely used items of electrical equipment. Improving motor efficiency benefits include, reduced power demand, lower...

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

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

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