Which item on a motor's nameplate helps to assess the maximum safe output power?

The service factor is a crucial specification on a motor's nameplate that indicates the maximum safe output power that the motor can deliver under specific conditions without risking damage or failure. It provides a safety margin and typically signifies how much additional load the motor can handle beyond its rated horsepower.

For example, a motor with a service factor of 1.15 can safely operate at 15% above its rated horsepower. This capacity allows for fluctuations in service conditions, such as increased ambient temperature or occasional overload. Therefore, understanding the service factor is essential for determining the motor's capabilities and ensuring that it is not subjected to excessive stress, which could lead to overheating or premature failure.

While the voltage rating indicates how much voltage the motor needs to operate properly, and the power factor reflects how efficiently the motor converts electrical power into mechanical power, neither directly informs about the safe maximum output. Phase configuration, which refers to the number of phases (single or three) that the motor is designed to operate within a power system, is also not a determinant of maximum safe output power. Therefore, the service factor is the most relevant specification when evaluating the safe operational limits of a motor.