Power Factor
Power factor is the ratio between the real power (P in kW) and apparent power (S in kVA) drawn by an electrical load. The reactive power (Q in kVAr)...
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...
Differential protection, the good old days
This morning I was explaining how differential protection works to a junior engineer. To give him something to read I opened up the NPAG (Network Protection...
Tips for a better Low Voltage Protection Discrimination Study
Carrying out a protection system discrimination study is critical to ensure the correct functioning of the electrical system in the event of faults. ...
Welcome back Bottle
‘Kept looking at a card, y’see? Kept looking at it. Welcome back Bottle. Gods below welcome home.
The Crippled God
A Tale of the Malazan Book of the...
Electromechanical Relays
Electromechanical relays have been the traditional backbone of electrical protection systems. While over recent years these have been replaced by microprocessor...
Understanding LV Circuit Breaker Fault Ratings
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...
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...
Motor Starting - Introduction
Motor starting and its associated problems are well-known to many people who have worked on large industrial processes. However, these things are, of course...
Laplace Transform
Laplace transforms and their inverse are a mathematical technique which allows us to solve differential equations, by primarily using algebraic methods...