From the monthly archives: December 2011

We are pleased to present below all posts archived in 'December 2011'. If you still can't find what you are looking for, try using the search box.

Understanding LV Circuit Breaker Fault Ratings

By Steven McFadyen on 12/18/2011 12:20 PM

I think this post is going to be helpful to several of our readers. While the IEC low voltage circuit breaker Standard [IEC 60947-2, Low voltage switchgear and controlgear - Part 2: Circuit-breakers] ha... read more..


Understanding Motor Duty Rating

By Steven McFadyen on 12/12/2011 8:05 AM

One of the comments on my Motor Starting Series was asking for something on duty cycles. Here it is.

As a... read more..


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..


myElectrical - Cable Sizing Tool Upgrade

By Steven McFadyen on 12/2/2011 4:56 AM

Our IEE cable sizing was wrote a few years ago and had become rough around the edges. I thought it was time to give the tool a service. Unfortunately when I looked under the hood I found cracked cylinde... read more..




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...

How to refer fault levels across a transformer

Over the past year or so I've been involved in on going discussions related to referring fault levels from the secondary of a transformer to the primary...

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...

Earth Electrode Resistance

Earthing of electrical systems is essential for the correct functioning and the protecting of life and equipment in the event of faults.  The earth electrode...

Gas Insulated or Air Insulated Switchgear

Various arguments exist around SF6 Gas Insulated (GIS) and Air Insulated (AIS) medium voltage switchgear. Recently we had to change a GIS design to AI...

E-Ink

Before the technical, some general information. E-ink display are found in a lot of e-readers, some mobile phones and similar devices and the intent is...

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. ...

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...

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...

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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