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..




Autonomous Vehicle Challenge

Two driverless and solar power vans have departed from Italy on their way to China via the silk road. During the 13,000 kM trip the vans will drive themselves...

Lightning Risk Assessment (IEC 62305)

IEC 62305 'Protection against lightning' requires a risk assessment be carried out to determine the characteristics of any lightning protection system...

What is a rectifier transformer?

I've recently come across this question a couple times browsing the internet. Decided to give a quick answer here. A rectifier transformer is a transformer...

Paths of Flight

GE have put together a time-lapse video shown flight take-off and landings at some airports. An interesting view:

How to Size Power Cable Duct

Some colleagues had an issue earlier in the week on sizing conduits to be cast in concrete for some power cables . It became clear that none of us had...

Variable Frequency Drive

Variable frequency drives are widely used to control the speed of ac motors.  This note looks at the mechanisms which enable drive units to control the...

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...

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...

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...

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...

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