Power Line Characteristics
by Dennis L. Feucht
Innovatia Laboratories
Design of off-line power supplies requires some knowledge of power-line characteristics. This article recounts a few basic design facts.
Power-Line Voltages and Frequencies
The typical US wall outlet supplies 120 V ac rms at 60 Hz. The range
of these parameters is contrasting indeed. While line voltage varies significantly
line frequency is locked to the NIST frequency standard, transmitted by
such stations as WWV in Fort Collins, Colorado at 10 MHz (exactly.) Power
companies, such as PGE in Portland, OR, tune in and synchronize their hydro
turbines to more significant figures than I could readily count while visiting
their control facility years ago....
Download the entire article here in Adobe Acrobat PDF format (20
kb)
Contact the author