Electrical and related buildings technology
The new standard IEC 61439 replaces the old 60439. Compared to the old standard, the new 61439 is a more clearly defined and takes into account the assembly...
Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is...
A UPS is an uninterruptible power supply. It is a device which maintains a continuous supply of electrical power, even in the event of failure of the...
Various techniques exist to enable the correct selection of batteries for UPS applications. The procedure described below is one of the more common. ...
When selecting a cable, the performance of the cable under fault conditions is an important consideration. It is important that calculations be carried...
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 other day I was talking to a colleague who is a building services consultant. Despite regularly specifying dry-type/cast resin transformers he was...
It wasn't so long ago I was telling someone that I don't use rules of thumb as most things are easily calculated anyhow. As it turns out I last week...
One of the requirements to ensuring that everything works is to have equipment selected, manufactured and verified [tested] to IEC standards. Not all equipment...
A load flow study is the analysis of an electrical network carried out by an electrical engineer. The purpose is to understand how power flows around...
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