Electromechanical Relays
Electromechanical relays have been the traditional backbone of electrical protection systems. While over recent years these have been replaced by microprocessor...
IEC Reference Designations
The IEC publishes a series of documents and rules governing the preparation of documents, drawings and the referencing of equipment. Depending on country...
How to Check a Circuit is Dead
If you want to check a circuit is dead (not live), you should always use the three point method. First check a known live circuit, then check the dead...
Medium Voltage Switchgear Room Design Guide
Many medium voltage (MV) indoor switchgear rooms exist worldwide. The complexity of these rooms varies considerably depending on location, function and...
Write your best report
Years ago I was told that you should always try to write the best report you can. Many years later I still think on this as one of the better pieces of...
The dc resistance of conductors
This is the first of two posts on the resistance of conductors. In the next post I will look at the ac resistance, including skin effect and we deal with...
E-Ink
Before the technical, some general information. E-ink display are found in a lot of e-readers, some mobile phones and similar devices and the intent is...
Maximum Demand for Buildings
Estimating maximum demand is a topic frequently discussed. Working out how much power to allow for a building can be very subjective . Allowing too much...
UPS Battery Sizing
Various techniques exist to enable the correct selection of batteries for UPS applications. The procedure described below is one of the more common. ...
Variable Frequency Drive
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...