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...
Introduction to Current Transformers
Current transformers (CTs) are used to convert high level currents to a smaller more reasonable level for use as inputs to protection relays and metering...
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...
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...
New Mail Chimp
We've been sending out Newsletters on a regular basis for a few weeks now. To do this we have been using Google's Feedburner service. While Feedburner...
Why use catalogues
I'm a fan of using manufacturers catalogues. There are two main reasons for this. Firstly, if your involved in the purchase of equipment, you will likely...
Batteries
A battery consists of one or more cells, each of which use stored chemical energy to produce electrical energy, There are many types of cells and these...
UPS - Uninterruptible Power Supply
A UPS is an uninterruptible power supply. It is a device which maintains a continuous supply of electrical power, even in the event of failure of the...
Laplace Transform
Laplace transforms and their inverse are a mathematical technique which allows us to solve differential equations, by primarily using algebraic methods...
IEC 60287 Current Capacity of Cables - Rated Current
In the previous note we looked at the approach taken by the standard to the sizing of cables and illustrated this with an example. We then looked at one...