Which factor might lead to an AC electric motor running too fast?

An AC electric motor running too fast is primarily influenced by excessive supply voltage. When the voltage supplied to the motor is higher than the motor's rated voltage, it can cause the motor to operate beyond its design speed. This situation affects the magnetic field strength in the windings, which can lead to an increase in speed due to the higher power input. This phenomenon can also result in overheating and potential damage to the motor if the voltage remains elevated for an extended period.

Understanding the impact of supply voltage is crucial in maintaining electrical systems. When motors are designed, they are rated for specific voltage levels, ensuring optimal performance and safety. Operating them with excessive voltage disrupts this balance, emphasizing the importance of monitoring voltage levels in any electrical system to ensure motors function correctly and within their designed parameters.