Temperature Estimation of Electric Motors of Electric Actuators

In the development of electric actuators, the electric motor to drive the actuator is quite often selected from a set of available motors that have been previously used on other similar programs, or based on legacy experience, or from those that are commercially available seeming to fit for the purpose. Scheduling and budgetary constraints pose a restriction on design and development of a new electric motor specifically for the required application. Generally, these electric motors have minimal weight but deliver maximum output power because of which they tend to heat up rapidly. Such rapid heating can lead to issues such as insulation damage or weakening of the strengths of permanent magnets used in the rotors of permanent magnet induction motors. In such cases, very early in the design phase, it becomes necessary to estimate the temperature rise of the electric motor in a cost effective and rapid way so that the best suitable motor that gives minimal temperature rise is selected. The prevalent methods of estimating the temperature rise of the electric motors during its operation use Finite Element Analysis (FEA), the calculations of which are complicated, requiring considerable computational and human resources. In this paper, a novel and simplified approach based on a set number of rational assumptions is proposed to estimate the temperature rise of electric motors to a reasonable accuracy such that selection is made based on the one that satisfies the program requirements to the utmost extent while keeping the project costs at a minimum.