2002: Upper Harmonics, A Short Treatise

By Ken Adachi http://educate-yourself.org/be/upperharmonicsexplained22may02.shtml May 22, 2002 The type of electrical waveform that most people are familiar with is the AC sine wave. AC stands for Alternating Current.  Seen on an oscilloscope, it’s the voltage sine waveform that we are most familiar with from physics textbooks; a gradually undulating, sinusoidal wave shape. It’s important to bear in mind that we are usually looking at a voltage waveforms on the oscilloscope, not current waveforms, but nevertheless we can understand the current flow based on what we see in the voltage waveform. Typically, half of the sine wave cycle occurs in the upper positive region of the oscilloscope graph, above the zero lines, and the other half of the cycle completes itself in the lower, negative region of the graph. In the upper positive region of the graph, the current is flowing in one direction only, but the intensity of the current is first gradually increasing and then […] Read More

2000: Alternating Current vs. Direct Current

All the principles of generating electricity had been worked out in the 19th Century, but by its end, these had only just begun to produce electricity on a large scale. The 20th Century has witnessed a colossal expansion of electrical power generation and distribution. The general pattern has been toward ever-larger units of production, using steam from coal- or oil-fired boilers. Economies of scale and the greater physical efficiency achieved as higher steam temperatures and pressures were attained both reinforced this tendency. U.S. experience indicates the trend: In the first decade of the century a generating unit with a capacity of 25,000 kilowatts with pressures up to 200-300 pounds per square inch at 400º-500º F (about 200º-265º C) was considered large, but by 1930 the largest unit was 208,000 kilowatts, with pressures of 1,200 pounds per square inch at a temperature of 725º F, while the amount of fuel […] Read More