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

The calculation of current in a three phase system has been brought up on our site feedback and is a discussion I seem to get involved in every now and...

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...

A couple of months ago I came Microsoft's OneNote and downloaded the 60 day free trail. Since then I have been using it regularly and now have a full license...

Many questions sent in to the site are in connection with motor starting and in particular star-delta.  For all but the simplest application, there is...

In three phase systems, the use of transformers with three windings (or legs) per side is common.  These three windings are often connected in delta or...

A fundamental concept behind the operation of alternating current systems is that voltage and current waveforms will be sinusoidal – a Sine Wave. This...

Lamps are the essential part of any luminaire. These are the light generating components. Since the advent of electrical lighting in the middle of the...

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...

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...