From the category archives: Buildings Technology

Electrical and related buildings technology

8 Motor parts and common faults

By Steven McFadyen on 12/6/2011 6:07 AM

Straight forward list of some common motor faults.  If I have missed any other common faults, please take a bit of time to add them in as a comment below. read more..


How to Calculate Motor Starting Time

By Steven McFadyen on 11/15/2011 2:00 PM

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 this. Failing that, hopefully at least som... read more..


Voltage Drop in Installations - Concepts

By Steven McFadyen on 9/27/2011 7:50 AM

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 int... read more..


8 Steps to Low Voltage Power Cable Selection and Sizing

By Steven McFadyen on 7/25/2011 2:48 AM

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 pow... read more..


Maximum Demand for Buildings

By Steven McFadyen on 6/16/2010 5:42 PM

Estimating maximum demand is a topic frequently discussed. Working out how much power to allow for a building can be very subjective . Allowing too much power results in additional equipment, increased ... read more..


3 Phase Loads

By Steven McFadyen on 5/4/2010 12:56 AM

Three phase systems are derived from three separate windings, either connected in delta or star (wye). Each winding can be treated separately, leading to the idea that the load in each winding can be vi... read more..


LED Replacement Light Bulb

By Steven McFadyen on 4/13/2010 12:08 AM

The inventor of the first visible light-emitting diode makes history again this year as it begins to show customers a 40-watt replacement GE Energy Smart® LED bulb available later this year or early... read more..


Lightning Risk Assessment (IEC 62305)

By Steven McFadyen on 9/27/2009 11:18 PM

IEC 62305 'Protection against lightning' requires a risk assessment be carried out to determine the characteristics of any lightning protection system to be installed. There is a lot of hype about about... read more..


110 or 230 Volts

By Steven McFadyen on 8/2/2009 10:50 PM

I've been considering a blog on the 110 or 230 Volt issue for a while.  While browsing the Internet I came across a great summary by Borat over at  engineering.com.  He ... read more..


IEC 61439 - The Switchgear Standard

By Steven McFadyen on 7/1/2009 3:08 AM

The new standard IEC 61439 replaces the old 60439. Compared to the old standard, the new 61439 is a more clearly defined and takes into account the assembly of pre-tested designs. .

Some key... read more..


UPS Sizing - Rules of Thumb

By Steven McFadyen on 4/30/2009 12:56 AM

It wasn't so long ago I was telling someone that I don't use rules of thumb as most things are easily calculated anyhow.   As it turns out I last week I ended up using what can only be describ... read more..


Three Phase Current - Simple Calculation

By Steven McFadyen on 3/1/2009 11:47 AM

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 again. While some colleagues prefer to remember... read more..


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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...

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...

Control Theory

Control theory looks at how systems work and are controlled from a mathematical view.  This note gives a brief introduction to some of the concepts – more...

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...

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...

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. ...

Inductance

When current flows within a wire, a magnetic field is created. The potion of this magnetic field perpendicular to the wire is called the magnetic flux...

Resistors

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

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...

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...

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