Which item on a motor's nameplate helps determine how much output power a motor can safely produce above its rated output power?

The service factor on a motor's nameplate is an important indicator of how much additional load a motor can handle beyond its rated output power. It provides a safety margin that helps engineers and technicians understand the motor's capacity for short-term overloads.

A service factor greater than 1.0 means that the motor is designed to operate safely under a load greater than its rated output for limited periods without overheating or sustaining damage. For example, a motor with a service factor of 1.15 can safely handle up to 15% more than its nominal rated horsepower for short bursts. This is particularly useful in applications where occasional overload occurs.

In contrast, the efficiency rating reflects how well the motor converts electrical energy into mechanical energy but does not indicate overload capacity. The power factor is related to the phase difference between voltage and current in the motor and affects overall energy consumption but does not denote additional allowable output power. The voltage rating specifies the voltage at which the motor operates optimally, but does not pertain to overload capability. Thus, the service factor is the most relevant item when assessing how much output power a motor can safely produce beyond its rated specifications.