What does the 'Duty' block mean on a motor nameplate?

What does the 'Duty' block mean on a motor nameplate?

• A. The temperature rating of the insulation
• B. The service factor at full load
• C. The length of time during which the motor can carry its nameplate rating safely
• D. The color code of the winding

Answer: (C)

Duty indicates how long a motor can run at its nameplate load before overheating under the specified cooling conditions. The block defines the operating duration or cycle for safe service, such as continuous operation (S1) or other duty patterns. This makes the correct choice the one that describes the length of time the motor can carry its nameplate rating safely. Insulation temperature rating (insulation class) is a separate specification, service factor relates to overload capability, and winding color is not part of duty.

Duty indicates how long a motor can run at its nameplate load before overheating under the specified cooling conditions. The block defines the operating duration or cycle for safe service, such as continuous operation (S1) or other duty patterns. This makes the correct choice the one that describes the length of time the motor can carry its nameplate rating safely. Insulation temperature rating (insulation class) is a separate specification, service factor relates to overload capability, and winding color is not part of duty.