Department of Energy explains power factor
DOE Explains Power Factor
Low power factor is inefficient and expensive. Low power reduces the distribution capacity by increasing the current flow. Correcting power factor enhances the efficiency of the electrical system and lowers electric bills.
To understand power factor, visualize a horse pulling a railroad cart from the side of a railroad track. The horse is pulling the cart at an angle to the direction of travel. The power required to move the cart is the working (real) power, the effort exerted by the horse is the total (apparent) power. Because of the angle of pull, not all the power exerted by the horse is used to move the cart. One can resolve this effort into two components, one that moves the cart along the direction of travel (functional power), and one that moves sideways (nonworking or reactive) power.
Power factor = Real Power ÷ Apparent Power
As an example, let’s say the real power is 100kVA, and the apparent power is 142kVA, then the Power Factor is 100 ÷ 142 = 0.70 or 70%, meaning that only 70% of the effort is doing useful work, while the rest (30%) is wasted.
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