What does the Power Factor (PF) measure in a motor's performance?

The Power Factor (PF) is a measure of how effectively electrical power is being converted into useful work output in a motor. It represents the ratio of real power (the actual power consumed by the motor to perform work) to apparent power (the total power flowing in the circuit) and is an important indicator of energy efficiency.

A higher Power Factor indicates that a higher proportion of the supplied power is being used to accomplish useful work, while a lower Power Factor suggests that more power is wasted in the form of reactive power, which does not perform any useful work. Thus, the Power Factor directly relates to the efficiency of energy usage in motors.

In contrast, the other choices do not accurately represent what the Power Factor measures. Voltage ratio pertains to the relationship between voltages in electrical circuits, current flow refers to the rate of charge movement, and temperature efficiency does not relate to the concept of Power Factor or motor performance in the context of electrical engineering.