Electromechanical Relays
Electromechanical relays have been the traditional backbone of electrical protection systems. While over recent years these have been replaced by microprocessor...
Switchboard - Forms of Internal Separation
IEC 61439 'Low-voltage switchgear and controlgear assemblies', specifies standard arrangements of switchboard (call forms of internal separation). The...
Star-Delta Motor Starting - Performance
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...
Fault Calculations - Introduction
Fault calculations are one of the most common types of calculation carried out during the design and analysis of electrical systems. These calculations...
Introduction to Current Transformers
Current transformers (CTs) are used to convert high level currents to a smaller more reasonable level for use as inputs to protection relays and metering...
What is an Open Delta Transformer
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...
Motor Efficiency Classification
Electric motors are one of the most widely used items of electrical equipment. Improving motor efficiency benefits include, reduced power demand, lower...
Cable Trumps
Bored at work and would rather be playing trump card game with you son. The next best thing (or not) maybe the online cable trump card game from AEI Cables...
Nikola Tesla
Nikola Tesla was born exactly at midnight on July 10, 1856 in the tiny village of Smiljan, Lika in Croatia. In his late teens, Tesla left the village to...
Low Voltage Fault Tables
The following tables provide quick order of magnitude fault levels for a a range of typical low voltage situations.