Understanding Motor Current
Motors draw different amounts of current depending on whether they're starting or running at their rated load. Understanding both helps with sizing conductors, breakers, and starting equipment.
Full load current
Full load current (FLC) is the current a motor draws while running at its rated horsepower. It depends on the motor's voltage, efficiency, and power factor.
Locked rotor current
Locked rotor current (LRC) is the much higher current a motor draws for a brief moment when it first starts, before it begins turning. It's typically several times the full load current.
Why the difference matters
Breakers, contactors, and conductors must handle the brief inrush of locked rotor current without nuisance tripping, while still protecting the motor during normal full-load running.