Cooling Fin Optimisation

The Motor-CAD user can easily vary geometric parameters such as fin spacing and tackle the variation in component temperatures to optimise the design (minimise the temperature rise). The user can also use the ActiveX capabilities within Motor-CAD to automate the process of varying a parameter and calculating the temperatures.

The majority of motors that have cooling fins are of the Totally Enclosed Fan Cooled (TEFC) type as shown below:

There can be benefits of fitting radial cooling fins to a Totally Enclosed Non Ventilated machine as shown below:

Motor-CAD has the ability to model a large variety of housing types as shown below:

The convection heat transfer for open and closed fin structures is calculated using proven analytical correlations. Algorithms are included to account for air leakage from open fins and for blockage due to terminal boxes, lifting bolts, etc. The parameterised nature of the Motor-CAD software gives a very powerful method for optimising design variables such as the fin spacing. For instance below we see a graph of the variation in winding temperature with fin spacing for a particular TENV design with radial fins:

In this case the optimum fin spacing is around 8mm. For fin spacing below the optimum the fin surface area is increased but the air flow is much reduced. For fin spacing above the optimum the fin surface area is much reduced but the air flow is increased.