SMMA MOTOR & MOTION COLLEGE — on November 1, 2006 from 1:00-5:00 pm at the Marriott St. Louis Airport Hotel, St. Louis, Missouri. Instructor for the half-day course is Richard Welch Jr., Senior Member IEEE, and Welch Enterprise.
WHO SHOULD ATTEND: Design, System & Application Engineers – Motor Users
SCOPE: This Tutorial is a must for everyone using electric motors. Every motor has a maximum continuous or rated operating temperature. Exceed this rated temperature and the motor can suffer permanent and irreversible thermal damage. To prevent this from happening we first derive and discuss the motor’s two-parameter thermal model.
This “standard” model is still used extensively by motor manufacturers and motor users alike to calculate the motor’s dynamic winding temperature during all possible modes of motor operation. Unfortunately, recent research has proven that this simple two-parameter model incapable of accurately predicting the motor’s dynamic winding temperature during power overload operation.
Next, the new four-parameter thermal model is derived and discussed. Using this four-parameter model you will learn why the motor’s winding heats up much faster than calculated by the two-parameter model and also learn why a temperature sensor mounted inside the motor may not be able to protect its winding from overheating or even burning up.
Using measured temperature data the improved accuracy of the four-parameter model is compared against the two-parameter model.
Finally, we will also discuss practical ways to reduce power dissipation inside the motor along with improving its heat transfer efficiency.