What does the horsepower rating of a motor measure?

The horsepower rating of a motor specifically measures the power output, which is the rate at which the motor can perform work. It is a function of torque and rotational speed, reflecting how much mechanical power the motor can generate in a given time period. This makes it a crucial specification for determining a motor’s capacity to drive loads, whether in industrial applications or in comfort systems like HVAC.

Understanding horsepower is essential for engineers when selecting a motor for a particular application to ensure it meets the required performance specifications. The other options, while related to motor performance, do not directly pertain to the measurement of power output. For example, motor efficiency relates to how well the motor converts electrical energy to mechanical energy but does not quantify output power. Additionally, voltage rating concerns the electrical potential required for the motor, and current draw during operation refers to the amount of current the motor will consume, both of which are important but not direct measures of power output.