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...

In a previous article I looked at the dc resistance of conductors and in this article we turn our attention to ac resistance. If you have not read the...

One of the requirements to ensuring that everything works is to have equipment selected, manufactured and verified [tested] to IEC standards. Not all equipment...

Battery powered cars are a hot topic and widely debated. The pros, cons, issues and time frames can be talked about endlessly. An article by the Telegraph...

Collection of links to various places with useful motor information. I’ll try and return to the page every now and again to update it with any motor notes...

Request to look at induction motor starting time have come up a few times on the site. Hopefully in this post, I give you guys some idea on how to calculate...

The following tables provide quick order of magnitude fault levels for a a range of typical low voltage situations.

The windings of many medium and small sized transformers are protected by restricted earth fault (REF) systems. The illustration shows the principal of...

When selecting a cable, the performance of the cable under fault conditions is an important consideration. It is important that calculations be carried...

The European Union is implementing a voluntary code of practice for participants with the aim of improving the overall efficiency of data centres. As part...