What is a common service factor for single-phase AC motors?

The service factor is a multiplier used to determine the allowable output of a motor under specific conditions. For single-phase AC motors, a common service factor is typically around 1.15. This indicates that the motor can operate at its rated horsepower, plus an additional 15% of that capacity under certain conditions without overheating or failing.

Using a service factor of 1.15 allows for some margin beyond the motor's rated load, accommodating for conditions such as increased ambient temperature, varying load conditions, or temporary overloads. This additional capacity can be particularly useful in applications where the motor may occasionally face higher demands without risking damage or performance issues.

In contrast, a service factor of 1.0 implies that the motor is not rated for any overload conditions, while higher service factors such as 1.25 or 1.5 are often reserved for specific applications requiring robust performance, like industrial or heavy-duty motors, which do not typically apply to common single-phase AC motors.