Smarter Electrical Distribution
The other day I came across an article in Technology Review on the development of a smart transformer. A professor at North Carolina State University is...
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...
Understanding Motor Duty Rating
One of the comments on my Motor Starting Series was asking for something on duty cycles. Here it is.
As a purchaser of a motor, you have responsibility...
How to refer fault levels across a transformer
Over the past year or so I've been involved in on going discussions related to referring fault levels from the secondary of a transformer to the primary...
Three Phase Power Simplified
A single phase system is perhaps the most common type of system most people are familiar with. This is what people have in their homes and what appliances...
Power Transformers - An Introduction
One of the fundamental requirements of an alternating current distribution systems it to have the ability to change the magnitude of voltages. It is more...
Frame Leakage Protection
While not as popular as it once was, frame leakage protection does still have some use in some circumstances. In essence frame leakage is an earth fault...
DC Component of Asymmetrical Faults
The image (reproduced from IEC 60909) shows a typical fault in an ac system. From the illustration it can seen that there is an initial dc component ...
Back to Basics - Ohm’s Law
Electrical engineering has a multitude of laws and theorems. It is fair to say the Ohm's Law is one of the more widely known; it not the most known. Developed...
Fault Calculation - Symmetrical Components
For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical...