What does the term "lock rotor current" refer to?

The term "lock rotor current" refers specifically to the current drawn by an electric motor when it is stalled, meaning that the rotor is not rotating despite the application of voltage. When a motor starts up, it typically encounters resistance and inertia, which can prevent it from reaching its operating speed. During this stalled condition, the rotor is effectively "locked," resulting in a significant increase in current draw compared to its normal running condition.

This current is crucial for understanding the motor's performance and electrical characteristics, particularly during start-up and fault conditions. Monitoring lock rotor current helps in protecting the motor from damage due to excessive heat and potential overload situations that can occur when the motor is unable to start properly. The other choices do not accurately define lock rotor current; for instance, the maximum current rating of a circuit or a type of overload protection pertains to different concepts in electrical systems.