We are pleased to present below all posts archived in 'April 2013'. If you still can't find what you are looking for, try using the search box.
Per unit fault calculations is a method whereby system impedances and quantities are normalised across different voltage levels to a common base. By removing the impact of varying voltages, the... read more..
For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical components, the unbalance system is broken dow... read more..
We have a sister note to this (Robots - Interesting Video), in which I have posted some videos of interesting robots developed by commercial corporations and institutions. While these are great... read more..
Coils of wire on the rotor carry a d.c. current which generates a magnetic field. A stator magnetic field is created using either permanent magnets or...
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...
The inventor of the first visible light-emitting diode makes history again this year as it begins to show customers a 40-watt replacement GE Energy Smart...
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...
Per unit fault calculations is a method whereby system impedances and quantities are normalised across different voltage levels to a common base. By removing...
The following tables provide quick order of magnitude fault levels for a a range of typical low voltage situations.
Depending where in the world you work, you are likely following one of two standards International Electrotechnical Commission (IEC) National...
Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using...
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...
A UPS is an uninterruptible power supply. It is a device which maintains a continuous supply of electrical power, even in the event of failure of the...
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