Analysis of the Endwinding Cooling Effects in TEFC Induction Motors

• Published in: IEEE transactions on industry applications Vol. 43; no. 5; pp. 1214 - 1222
• Main Authors: Boglietti, A., Cavagnino, A.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2007; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cooling; Electrical resistance measurement; Endwinding cooling; Extraterrestrial phenomena; forced-convection heat exchange; Frames; Heat exchangers; Heat transfer; Induction motors; Lamination; Mathematical models; Motors; Prototypes; Stator windings; Studies; Testing; thermal analysis; Thermal resistance; totally enclosed fan-cooled (TEFC) induction motors; Velocity measurement
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2007.904399

This paper deals with the endwinding cooling problems of totally enclosed fan-cooled (TEFC) induction motors. In order to obtain information about the phenomena involved in the motor end space, three "ad hoc" prototypes have been built. The complete test-bench setup, together with the followed test procedures, is reported in detail. The measurement results have shown that all the motor-part overtemperatures (winding, endwindings, stator lamination, and external motor frame) decreasing, with the inner air speed increasing. The measured motor overtemperatures and losses allow the thermal-resistance identification of a simplified thermal model suitable to describe the thermal behaviors of the prototypes. By the endwinding-to-motor frame thermal resistance, the related heat-exchange coefficients have been evaluated as a function of the rotor speed. The proposed procedure allows separating the forced-convection contribution by the other thermal-exchange phenomena that occur in the end-space regions. The obtained heat-transfer coefficients are in agreement with the results reported in the past literature.