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...

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

I was having a conversation the other day about voltage levels.  While everyone was in agreement that low voltage was 1000 V and less, there was more confusion...

We have a sister note to this (Robots - Interesting Video), in which I have posted some videos of interesting robots developed by commercial corporations...

Many medium voltage (MV) indoor switchgear rooms  exist worldwide. The complexity of these rooms varies considerably depending on location, function and...

It starts with me reading one of the Horrible History books with my son (Groovy Greeks). Arrows were mentioned which lead to the discussion of the bodkin...

Traditionally generation of electricity has involved rotating machines to produce alternating sinusoidal voltage and current (a.c. systems). With the development...

Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is...

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)...

In electrical engineering, Network Theory is the study of how to solve circuit problems. By analyzing circuits, the engineer looks to determine the various...