Harmonics are currents or voltages with frequencies that are integer multiples of the fundamental power frequency. Harmonic frequencies from the 3rd to the 25th are the most common range of frequencies measured in electrical distribution systems.
Power Factor Studies
Power Factor is a measure of how efficiently electrical power is consumed. In the ideal world Power Factor would be unity (or 1). Unfortunately in the real world Power Factor is reduced by highly inductive loads to 0.7 or less. This inductance is caused by equipment such as motors, compressors, transformers and fluorescent lighting ballasts and welding sets, etc.