13-23: Direct Drive Motor Design - Improving Product Availability by

The horsepower and speed required for a given fan depends on many factors, including maximum tip speed, blade design, blade pitch, and required CFM. There are an infinite number of HP/RPM/shaft combinations that could be requested from a direct drive motor manufacturer. With careful design, it is possible to create a "universal" motor that covers a wide range of requirements. This paper discusses characteristics that must be considered when designing a universal direct drive motor. Pros and cons of this approach will be discussed. Comparisons between a universal motor design and a more traditional motor design concept will be made.