Switchboard - Forms of Internal Separation
IEC 61439 'Low-voltage switchgear and controlgear assemblies', specifies standard arrangements of switchboard (call forms of internal separation). The...
Calculating Cable Fault Ratings
When selecting a cable, the performance of the cable under fault conditions is an important consideration. It is important that calculations be carried...
How to Size Power Cable Duct
Some colleagues had an issue earlier in the week on sizing conduits to be cast in concrete for some power cables . It became clear that none of us had...
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...
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...
What is a rectifier transformer?
I've recently come across this question a couple times browsing the internet. Decided to give a quick answer here. A rectifier transformer is a transformer...
Multimeter
Multimeters are undoubtedly the most common item of electrical test equipment in use. Often it is the first piece of equipment people will turn to when...
Generator Sizing & Operation Limits
When selecting a generator, there are inherent limits on the active and reactive power which can be delivered. Generators are normally sized for a certain...
Lightning Protection and Earth Electrode Resistance
Most installations involve some form of lightning protection system which is connected to an earth electrode. The function of the earth electrode is to...
Robotics - Home Innovations
We have a sister note to this (Robots - Interesting Video), in which I have posted some videos of interesting robots developed by commercial corporations...