This report aims to identify, in terms of economic and technical aspects, an electric motor whose characteristics meet a proposed replacement of a direct current (DC) motor in an aluminum extrusion plant, whose preventive maintenance has in the last years, the problem of technical and operational orders. Data relating to the preventive maintenance of motors in operation were used to estimate the performance of an induction motor in combination with an inverter for speed and torque control. The advantages were determined, and the investment costs can be reduced by maintenance. It was observed that the market offers an innovative solution by the use of a permanent magnet synchronous motor (PMSM), which is a brushless, alternating current (AC) motor, with reduced dimensions, and offers the same power as a three-phase induction motor (TPIM). Joule losses in the rotor are negligible because the rotor is fit internally with rare-earth-doped neodymium-iron-boron permanent magnets, which also minimizes motor temperature, thereby increasing its useful life. Estimates determined that the gains derived from preventive maintenance would be even greater than those expected for the induction motor. Simulations conducted in MATLAB showed that, in terms of energy efficiency, the PMSM is presently the most appropriate replacement for the DC motor.
Key words: Brushless, permanent magnets, preventive maintenance, retrofitting, electric motor.