A thermal analysis was performed on a large 10 HP electric motor to estimate the maximum case temperature during operation at 70% efficiency. The analysis accounted for heat transfer through natural convection from exposed surfaces to the dirty ambient air environment, and conduction through the motor mounting plate. The results showed that using an aluminum housing instead of the baseline steel housing provided a considerable cooling advantage and lower operating temperatures.

1. LARGE DC ELECTRIC MOTOR
THERMAL ANALYSIS
2/11/2016
Don Blanchet
3B Associates
339-234-3544

2. Goals
 Perform a simple thermal analysis of a
large 10 HP electric motor.
 Estimate the maximum case
temperature at a 70% efficiency
operating point
 Heat transfer modes
– Natural convection to ambient air
– Conduction through mounting plate

3. Natural Convection
 The natural convection heat transfer
coefficient has been de-rated by 50%
to allow for the very dirty and dusty
environment for this specific
application.
 Cleaning maintenance is not practical.

4. Model
14 inch dia

5. FEA mesh

6. Heat transfer modes
Conduction to
Mounting surface
Natural convection to ambient
Through exposed surfaces

7. Results: steel housing

8. Results: aluminum housing

9. Conclusion
 Cast aluminum offers a considerable
cooling advantage over the baseline
steel housing.