Differential protection, the good old days
This morning I was explaining how differential protection works to a junior engineer. To give him something to read I opened up the NPAG (Network Protection...
Power Factor
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)...
How to Size Current Transformers
The correct sizing of current transformers is required to ensure satisfactory operation of measuring instruments and protection relays. Several methods...
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...
Photovoltaic (PV) - Electrical Calculations
Photovoltaic (PV) cells (sometimes called solar cells) convert solar energy into electrical energy. Every year more and more PV systems are installed...
Lead Acid Batteries
Lead acid batteries are cost effect and reliable, making them suitable for many applications.This note examines topics of interest associated with the...
Understanding electric motor insulation & temperature
Anyone specifying or using electric motors should have a basic understanding how the insulation is related to temperature. Three classes of insulation...
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...
IEC Document Designation
Often document control is dictated by project requirements, for example a particular organisation may have an existing numbering system. Existing company...
Robots - Interesting Videos
The robot folding towels post below was interesting enough at the time to post a link. Recently I’ve come across a couple of other interesting videos...