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.

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 circuit and finally recheck the live circuit. Carrying out the procedure ensures that the meter is working before and after testing for the dead circuit. A few additional measurement tips to make things safe:

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Tip – Latitude and Longitude on Large Scale Plans

If you are working on a large plan, get the real coordinates [latitude, longitude] for two or more points and add them to the drawing. That way you can always work out the scale and dimensions.

I know that drawings have scales, grids etc. on them and they are supposed to work. However, many times I've come across drawings where things don’t tie up. There can be hundreds of reasons ...

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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 in 1827 by Georg Ohm the law defines the relationship between voltage, current and resistance in an electric circuit.

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What does N+1 mean?

The term 'N+1' relates to redundancy and simply means that if you required 'N' items of equipment for something to work, you would have one additional spare item. If any one item of equipment breaks down, every thing can still work as intended. For example if you need two UPS for a small data centre, you would install three to have N+1; if you have a water pump in your building your would install a second one for N+1; if you require three transformers to power your facility you would install four for N+1.

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Always Use PPE

A lot of our members work in countries where PPE (personal protective equipment) is regulated or they work for companies/organizations which take employee safety seriously. Unfortunately, there are places/companies where little or not thought is given to safety and daily peoples lives are put at risk. If you are working on live circuits then you should always use PPE.

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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 Fallen 10, Steven Erikson

If you recognise the quote then you already know what an exciting journey this series by Steven Erickson is. If not then the only thing I really need to say is that you must read the series.

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Differential protection, the good old days

This morning I was explaining how differential protection works to a junior engineer. To give him something to read I opened up the NPAG (Network Protection and Automation Guide, by Areva) and turned to Chapter 10 ‘Unit Protection of Feeders’. I was immediately confronted with Marz and Price, circulating current systems, balanced voltage systems, high impedance series connected relays, illustration like the attached, etc. ... and remembered my early years. A time when if you mentioned differential protection to an electrical engineer, they would turn and run in the opposite direction.

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Voltage Drop in Installations - Concepts

Problems on achieving maximum voltage drop within an installation come up often. Depending where you live, local regulations will have different limits on maximum allowable voltage drop, however the intent of all of these is to ensure sufficient voltage is available at the equipment so that if functions correctly. Specified voltage drops are generally not for an individual cable but for the full installation; from the point of supply connection to the final equipment. Thus the overall voltage drop is a combination of individual voltage drops across multiple cables.

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New Mail Chimp

We've been sending out Newsletters on a regular basis for a few weeks now. To do this we have been using Google's Feedburner service. While Feedburner is a fantastic product (and free of cost), to improve our Newsletter delivery we have changed to a paid service. All Newsletter and update emails are now being delivered by mailChimp (http://mailchimp.com).

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Motor Starting - Introduction

Motor starting and its associated problems are well-known to many people who have worked on large industrial processes. However, these things are, of course, less familiar to others.  This post is a quick introduction to motor starting.

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Back to basics - the Watt (or kW)

When thinking about watts (W) or kilowatt (kW = 1000 W) it can be useful too keep in mind the fundamental ideas behind the unit. Watt is not a pure electrical or mechanical unit, but is a measure of the rate of doing work.  Let start at the beginning and understand the meaning of work

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8 Steps to Low Voltage Power Cable Selection and Sizing

A recurring theme on our forums is cable sizing. Now many installations are unique and require special consideration. However, a lot of the time things are just repeated. When looking at low voltage power cables I generally always start with the same basic strategy.

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Understanding Motor Duty Rating

One of the comments on my Motor Starting Series was asking for something on duty cycles. Here it is. As a purchaser of a motor, you have responsibility...

Nikola Tesla

Nikola Tesla was born exactly at midnight on July 10, 1856 in the tiny village of Smiljan, Lika in Croatia. In his late teens, Tesla left the village to...

Famous Scientists

Here’s list of some famous scientists. Deliberately short, with the aim to provide a quick memory jog or overview. If your looking for more detailed information...

How to Calculate Motor Starting Time

Request to look at induction motor starting time have come up a few times on the site. Hopefully in this post, I give you guys some idea on how to calculate...

The ac resistance of conductors

In a previous article I looked at the dc resistance of conductors and in this article we turn our attention to ac resistance. If you have not read the...

Write your best report

Years ago I was told that you should always try to write the best report you can.  Many years later I still think on this as one of the better pieces of...

Maxwell's Equations - Gauss's Electric Field Law

Gauss's Electrical law defines the relation between charge ("Positive" & "Negative") and electric field.  The law was initially formulated by Carl Friedrich...

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...

Arc Flash Calculations

Working in the vicinity of electrical equipment poses an hazard. In addition to electric shock hazard, fault currents passing through air causes Arc Flash...

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 ...

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