The DESIGN letter noted on a motor nameplate indicates what characteristic?

The characteristic indicated by the DESIGN letter on a motor nameplate is the torque characteristics of the motor. This designation helps identify the type of starting and operational torque that the motor is designed to provide. Depending on the application, the motor may require a specific torque profile to function efficiently, and the DESIGN letter categorizes this aspect.

Understanding the torque characteristics is essential for selecting the right motor for specific applications, particularly in industries where starting and operational behavior directly affect performance. For example, a motor with a higher torque design may be better suited for tasks that involve heavy loads at start-up, ensuring that the motor can handle the demands placed upon it from the outset.

In contrast, insulation class, duty rating, and starting current denote different characteristics entirely, such as thermal protection (insulation class), the extent of operational use (duty rating), and the initial surge of current upon starting (starting current). Each of these plays a vital role in motor performance but does not pertain to the specific torque capabilities as indicated by the DESIGN letter.