Jim Bryan
EASA Technical Support Specialist
What is voltage variation? Voltage variation is the deviation of voltage from the rated voltage; NEMA MG1 Section 12 allows a plus or minus 10% variation from rated voltage. That rating assumes balanced voltages and acknowledges that motor performance will not necessarily be the same as at rated voltage. Note: The tolerance for voltage unbalance is only 1%, an order of magnitude less than the 10% voltage variation tolerance. For more information on this subject, see the December 2007 edition of Currents for an article on voltage unbalance titled “Unbalanced Voltages and Electric Motors.”
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