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 ...
Tech Topics/Application Notes - Siemens
There are a lot of interesting two page type notes on various medium voltage topics – switchgear, circuit breakers, bus systems etc. It is on the Siemens...
Arc Flash Calculations
Working in the vicinity of electrical equipment poses an hazard. In addition to electric shock hazard, fault currents passing through air causes Arc Flash...
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...
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...
What is Aircraft Ground Power
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...
Lead us, Warleader
Delum, who had watched all in silence, his face empty of expression, now spoke in turn. ' "Lead us, Warleader, into glory."'
Reading is something I do...
Cable Sizing Tool
Our cable sizing tool is one of the more popular tools on the site. The tool enables cables to be sized in compliance with BS 7671 (the IEE Wiring Regulations...
Generation of a Sine Wave
A fundamental concept behind the operation of alternating current systems is that voltage and current waveforms will be sinusoidal – a Sine Wave. This...
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...