From the monthly archives: November 2009

We are pleased to present below all posts archived in 'November 2009'. If you still can't find what you are looking for, try using the search box.

Lightning Protection and Earth Electrode Resistance

By Steven McFadyen on 11/22/2009 7:48 PM

Most installations involve some form of lightning protection system which is connected to an earth electrode.  The function of the earth electrode is to dissipate the lightning strike safely in to ... read more..


1,000 kV UHV First for China

By Steven McFadyen on 11/3/2009 8:33 PM

At the beginning of the year China put the world's first 1,000 kV UHV transmission system into operation. Transmitting power at over a million volts is just amazing.  Some key facts about the syste... read more..




Electromechanical Relays

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  While over recent years these have been replaced by microprocessor...

How to Check a Circuit is Dead

If you want to check a circuit is dead (not live), you should always use the three point method. First check a known live circuit, then check the dead...

Welcome back Bottle

‘Kept looking at a card, y’see? Kept looking at it. Welcome back Bottle. Gods below welcome home. The Crippled God A Tale of the Malazan Book of the...

Electric Motors

Collection of links to various places with useful motor information. I’ll try and return to the page every now and again to update it with any motor notes...

Tech Topics/Application Notes - Siemens

There are a lot of interesting two page type notes on various medium voltage topics – switchgear, circuit breakers, bus systems etc. It is on the Siemens...

Variable Frequency Drive

Variable frequency drives are widely used to control the speed of ac motors.  This note looks at the mechanisms which enable drive units to control the...

Low Voltage Fault Tables

The following tables provide quick order of magnitude fault levels for a a range of typical low voltage situations.

IEC 60287 Current Capacity of Cables - An Introduction

IEC 60287 "Calculation of the continuous current rating of cables (100% load factor)" is the International Standard which defines the procedures and equations...

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...

Resistors

Resistors are electronic components that oppose the flow of current.  Manufactured in various types and ranges they have a wide application to electronics...

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