Sensitivity to Voltage Levels and Voltage Fluctuation

Every piece of electrical equipment will operate within a range of voltage levels, however not necessarily with optimal performance. When the voltage level falls outside of its operational range, a device may be unable to start or operate, it may malfunction or the device may be damaged. The width of the voltage level range within which a device will operate is a measure of its sensitivity to voltage level. A device that will operate fairly well within a range of +/-10% of nominal voltage would be considered to have a relatively low sensitivity to voltage level or voltage fluctuations. A device that operates properly only when the voltage level is within +/-5% (or less) of nominal voltage would be considered to be sensitive to voltage level or fluctuations. Three phase motors are very tolerant of voltage level fluctuations while the electronic controls for the same motor might be quite sensitive.