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...

One of the fundamental requirements of an alternating current distribution systems it to have the ability to change the magnitude of voltages.  It is more...

Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using...

This article gives an introduction to IEEE 485 method for the selection and calculation of battery capacity.

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...

The International System of Units (abbreviated SI) is the world's most widely used system of units.  The system consists of a set of units and prefixes...

Laplace transforms and their inverse are a mathematical technique which allows us to solve differential equations, by primarily using algebraic methods...

Just added a page to the tools, which will allow you to calculate the synchronous speed, slip and rated torque for an induction motor. Not a particularly...

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...

I've been considering a blog on the 110 or 230 Volt issue for a while.  While browsing the Internet I came across a great summary by Borat over at  engineering...