Cooling system for totally enclosed motor - has internal air ducts adjacent to external ducts in the stator frame

摘要

The machine has forced air circulation inside the stator frame. Air is forced by an internal fan through ducts (5E) in the stator frame joining the end winding compartments. Parallel to these ducts (5E) are further ducts (13) through which air external to the machine is forced by an external fan. The stator frame typically also has external axial ribbing (2A) giving additional cooling surface which is in the external air stream. The method of construction is suitable for use in cast frames. The necessary external, and also internal, ducts can be formed by casting tubes into the frame. By arranging the tubes from the respective air circuits clost together the effective heat transfer from internal to ambient air is improved.