Steven McFadyen's Articles

Steven is a Chartered electrical engineering consultant with considerable experience on major internationally recognised and award winning projects in Europe, South East Asia, and the Middle East. His expertise has been called on for numerous technically challenging projects in power systems, airports, rail, mining, pharmaceutical, datacentre, and other industries.

Low Voltage Circuit Breakers

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 by faults on a system which can lead to dangerous situations for both people and the system itself.   In addition to providing system protection, circuit breakers enable parts of the electrical distribution to be isolated for operation and maintenance.

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Post Authorship

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 content to users by linking to the original and penalising sites which duplicate content and don’t add value.  At myElectrical we  support the authorship tools for our Opinion and Notes posts.

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Lighting Design - An Introduction

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 lamps and then candles were invented. During the 18th and early 19th centuries, the technology of oil lamps improved and gas lighting was developed. Starting in the middle of the 19th century, electrical lighting became available with the invention of the fluorescent and incandescent lamps.

Lighting design is the field of creating light, its application and use by people. Lighting design starts by developing the objectives and then quantifying these by specifying the criteria. When looking objectives, the lighting designer will consider:

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International System of Units (SI System)

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.

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Standard Cable & Wire Sizes

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 States, wire sizes are commonly measured in American Wire Gauge (AW).

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Equipment Verification (to IEC Standards)

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 the responsibility of the engineers in the procurement and construction process to ensure that only equipment meeting these requirements is used.

If your involved in this activity you most likely already know what to do and have your own methods for approaching this issue. If your new to this or have just been tasked with verifying equipment meets requirements, hopefully this post will get you started.

Ensuring compliance is not complicated, but there are a couple of things you aware of.

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Batteries

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 the many battery types in use.

Batteries are divided in to primary and secondary:

  • Primary batteries – have an irreversible chemical action and can only be used once
  • Secondary batteries – have a reversible chemical action and can be recharged

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UPS Battery Sizing

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 (see link at the bottom of the page).

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Battery Sizing

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

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Introduction to Lighting

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 overview of these concepts.

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Alternating Current Circuits

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 adding to it bit by bit as I start closing pages down in the Wiki. Hopefully by the time the Wiki is fully depreciated, we should have a reasonable article here.

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Electromechanical Relays

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 still many older  electromechanical relays in service.

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Cables for MV Power Distribution - Earthed versus Unearthed Systems

Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is...

IEC Reference Designations

The IEC publishes a series of documents and rules governing the preparation of documents, drawings and the referencing of equipment.   Depending on country...

Low Voltage Switchroom Design Guide

Low voltage (LV) switchrooms are common across all industries and one of the more common spatial requirements which need to be designed into a project...

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...

Restricted Earth Fault Protection

The windings of many medium and small sized transformers are protected by restricted earth fault (REF) systems. The illustration shows the principal of...

Laplace Transform

Laplace transforms and their inverse are a mathematical technique which allows us to solve differential equations, by primarily using algebraic methods...

Introduction to Current Transformers

Current transformers (CTs) are used to convert high level currents to a smaller more reasonable level for use as inputs to protection relays and metering...

Material Properties

Everything physical in electrical engineering from insulations to conductors revolves around materials. Here we are listing common materials along with...

Why a Sine Wave?

I received this question by email a few weeks. First thoughts was that it is a product of the mathematics of rotating a straight conductor in a magnetic...

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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