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IEC 61439 Verification Methods

The (relatively new) switchgear and control gear standard, IEC 61439 'Low-voltage switchgear and controlgear assemblies' has three methods which can be...

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 ...

ABB Technical Guides - Motor Operation

ABB has produced a range of technical guides that offer concise explanations of the major technologies and technical issues in low voltage AC drives. ...

MIT OpenCourseWare

MIT OpenCourseWare, makes the materials used in teaching all MIT subjects available on the Web, free of charge, to any user in the world.

Introduction to Lighting

When looking at the design of a lighting scheme it is useful to have an understanding on the nature of light itself and some of the basic theory associated...

HTML Symbol Entities

HTML supports a variety of entity symbols which can be entered using either numbers or an entity name.  The number or name is preceded by the ‘&’ sign...

Why use catalogues

I'm a fan of using manufacturers catalogues. There are two main reasons for this. Firstly, if your involved in the purchase of equipment, you will likely...

How a Digital Substation Works

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

Closed Doors

"I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers that might be wrong...

Capacitors - Energy Storage Application

Capacitors have numerous applications in electrical and electronic applications.  This note examines the use of capacitors to store electrical energy....

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