E-Motors: How Thermal Transfer of Stator Mounting Solutions Affect Power Efficiency

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Fixing a stator into a housing can be achieved using numerous methods. Each of these have advantages and disadvantages. Take a tolerance ring as an example; the tolerance ring is one of the simplest methods of stator mounting and can greatly reduce assembly costs when compared to heat shrink press fit and adhesive solutions. The tolerance ring can also take up the mating component tolerances. This is true even for variable temperature effects such as having different thermal expansion coefficients for the aluminium housing and the iron-based stator. However, one disadvantage of the tolerance ring is that the heat transfer from the stator to the housing is not as high as alternative solutions, which can cause power efficiency issues when the motor coils heat up and the resistance increases.

Research by our engineers has produced a solution to this problem. The addition of an aluminium layer onto the steel tolerance ring improves contact between the components and also exploits the higher thermal transfer value of aluminium.