Unlike their fractional and integral horsepower cousins, which are “rated” using standards set by established organizations, there are no standards for rating small fractional and sub-fractional horsepower DC and stepper motors. Each manufacturer must choose its own rating system. Trying to compare published data from multiple manufacturers is therefore a tedious task.

To make the situation worse, engineers today routinely download PDF datasheets from the Internet or receive them via email, sources from which important supplemental information is often omitted. This means that important details regarding the methods by which technical figures are arrived at are not readily available, preventing technical engineers from making the most informed decision possible when choosing a DC motor for an application.

The example provided in this white paper illustrates the drastically different standards of manufacturers’ ratings and how they prevent engineers from properly informing themselves.