From the monthly archives: May 2013

We are pleased to present below all posts archived in 'May 2013'. If you still can't find what you are looking for, try using the search box.

Introduction to Cathodic Protection

By Steven McFadyen on 4/25/2013 12:53 PM

If two dissimilar metals are touching and an external conducting path exists, corrosion of one the metals can take place.  Moisture or other materials acting as an electrolyte between the metals... read more..


Frame Leakage Protection

By Steven McFadyen on 4/18/2013 1:12 PM

While not as popular as it once was, frame leakage protection does still have some use in some circumstances.  In essence frame leakage is an earth fault type protection.  A current transfo... read more..


What is Aircraft Ground Power

By Steven McFadyen on 4/11/2013 12:53 PM

Ever wondered what kind of power an aircraft uses when parked at the airport stand.

Normally the aircraft generates it own power, but when parked with the engines switched off power provided ... read more..


Photovoltaic (PV) - Utility Power Grid Interface

By Steven McFadyen on 4/4/2013 12:47 PM

Photovoltaic (PV) systems are typically more efficient when connected in parallel with a main power gird. During periods when the PV system generates energy this can be utilized and the grid energy u... read more..




Periodic Electrical Installation Inspection – How Often?

How often installations are inspected is up to the owner of the installation, provided such durations do not exceed any regulatory maximums in force. ...

ANSI (IEEE) Protective Device Numbering

The widely used United Sates standard ANSI/IEEE C37.2 'Electrical Power System Device Function Numbers, Acronyms, and Contact Designations' deals with...

Fault Calculation - Per Unit System

Per unit fault calculations is a method whereby system impedances and quantities are normalised across different voltage levels to a common base.  By removing...

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...

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...

Motor Insulation

Insulation on a motor prevents interconnection of windings and the winding to earth.  When looking at motors, it is important to understand how the insulation...

IEC 61439 - The Switchgear Standard

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...

RLC Circuit, Resistor Power Loss - some Modelica experiments

Modelica is an open source (free) software language for modelling complex systems. Having never used it before, I thought I would download a development...

Why is electricity so hard to understand?

It's been a busy few months on different projects or busy couple of decades depending on how I look at it. I can say that on the odd (frequent) occasion...

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...

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