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.

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 myCableEgineering.com have tonnes of useful technical information on power cables.  By adding our myElectrical cable notes, this resource, it is now even better. 

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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 advantages and disadvantages.

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Photovoltaic (PV) Panel - Performance Modelling

In an earlier note on the site [Photovoltaic (PV) - Electrical Calculations], the theory of solar (PV) cell calculations was introduced.  In particular the post looked at the PV cell equivalent circuit and the electrical characteristics of the cell.  This note expands on the previous post and shows how we can use tools like MatLab to model the performance of a complete solar panel.

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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 the electrical network. Carrying out a load flow study assists the engineer in designing electrical systems which work correctly, have sufficient power supplied by the power grid, where equipment is correctly sized, reactive power compensation is correctly placed and transformer taps are optimised.

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Tips for a better Low Voltage Protection Discrimination Study

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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What is an Open Delta Transformer

In three phase systems, the use of transformers with three windings (or legs) per side is common.  These three windings are often connected in delta or star, resulting in common transformer configurations such as delta-delta or delta-star.  An open delta transformer is a special arrangement which uses only two windings.

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Star-Delta Motor Starting - Performance

Many questions sent in to the site are in connection with motor starting and in particular star-delta.  For all but the simplest application, there is merit in performing a more detailed study.  Carrying out a software study allows both the electrical performance and that of the connected mechanical systems to be evaluated.

This note illustrates by example one possible approach to studying the performance of a star-delta motor starting circuit.

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Electromagnetic Fields - Exposure Limits

Exposure to time varying magnetic fields, from power frequencies to the gigahertz range can have harmful consequences.  A lot of research has been conducted into identifying these effects and developing recommended safe exposure limits.

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Induction Motor Equivalent Circuit

Induction motors are frequently used in both industrial and domestic applications.  Within the induction motor, an electrical current in the rotor is induced by a varying magnetic field in the stator winding. The rotor current produces it's own magnetic field, which then interacts with the stator field to produce torque and rotation.   

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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 of power electronics during the last several decades, semi-conductor devices are now frequently used to convert direct current (d.c.) to a.c. to power conventional alternating current systems.

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How a Digital Substation Works

Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using copper cables.  With advances in digital technology, communications and standards, this is now changing to what is known as the digital substation.   This is an introduction to the digital substation and the bits and pieces which go into making up the system.

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A mechanical engineering paper, some history and memories

I was digging in my bookshelf and came across the 80th Anniversary Association of Mine Resident Engineers, Papers and Discussions Commemorative Edition (May 2004). Within it's dark covers, is a paper I wrote many years ago. Reading through the paper, brought memories of my arrival in South Africa. It seemed a shame to lose them all again; so this is my first off-topic post in a while.

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Fault Calculations - Typical Equipment Parameters

A frequent problem in fault calculations is the obtaining of equipment parameters.  While it is always preferable to use the actual parameters of the equipment...

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...

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...

How to Write an Electrical Note

Electrical notes are a collaborative collection of electrical engineering information and educational material. Any registered user can add content. ...

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...

Three Phase Power Simplified

A single phase system is perhaps the most common type of system most people are familiar with. This is what people have in their homes and what appliances...

Fault Calculation - Symmetrical Components

For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical...

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...

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...

GE's Shingijutsu Factory

GE's latest thinking on product manufacturing is he Shingijutsu philosophy or Lean production system. They have started applying this at the Louisville...

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