Monthly Archives: February 2014

Electric Power Quality and Lighting (part 1)

Posted May 26 2012 by Sufi Shah Hamid Jalali in Energy Efficiency, Lighting with 2 Comments
on Electrical Engineering Portal
Original Source: Wolsey, Robert, Power Quality, Volume 2, Number 2, February 1995 (Lighting Research Center (LRC) and Power Quality)


Concerns about the effects of lighting products on power distribution systems have focused attention on power quality. Poor power quality can waste energy and the capacity of an electrical system; it can harm both the electrical distribution system and devices operating on the system.

There are many elements in a power system that affects two major parameters; power factor and harmonics. Electric motors, some lighting fixtures, transformers and other inductive and capacitive appliances introduce reactive power to the system, and thus involved in damaging the power factor. These components need reactive power to work.

Nonlinear loads like UPS, computer systems, fluorescent fixtures, CFLs, digital electronics, etc. are distorting current waveforms and introducing harmonics to the power system.

This technical article will help lighting specifiers and consumers better understand power quality, so that they can more confidently select energy-efficient lighting products. Continue reading

Take another look at your drives!


Source : mepca Engineering

Vacon UK – Using variable speed drives (VSDs) is a great way of saving energy but, if your VSDs are more than five years old, it’s time to take another look at them, says Stephen Takhar, Managing Director of ac variable speed drive expert, Vacon UK.

For the last decade, the technical press has been awash with stories about the energy savings that can be made by fitting VSDs. The stories are true, which is why many companies have already installed VSDs. When engineers in these companies see the VSD energy saving stories, they probably think they’ve been there and done that, but are they justified in sitting back and enjoying the glow of a job well done? That depends on the age of their VSDs. If they’re just a few years old, it’s unlikely that further action is needed. But if the VSDs are over five years old, it’s a different story. Continue reading