Análise da viabilidade do uso do acoplamento magnético em substituição ao inversor de frequência.

Abstract

In this work is presented the analysis of two case studies that approach the magnetic coupling technology, aiming to verify the feasibility of its use in substitution to the variable frequency drive (VFD) to use with the induction motor. Magnetic coupling is a type of equipment that uses the properties of permanent magnets to transmit torque between two rotors, without physical contact between the parts. The main gains from its use against VFD's are the nonpropagation of vibrations between drive and load, high tolerance to misalignment and no harmonic generation. In addition, they can replace VFD's in many applications that do not require a high precision control on torque and speed, and also bring numerous benefits to industries due to their low maintenance cost. Even a few years after its introduction, this technology is still little known nationally and few studies and national research address the theme. In the first case study analyzed, it is possible to prove the feasibility of using couplings in applications with speeds close to the nominal value of the machine. In tests performed in laboratory, it was found a power consumption close to the VFD's, with a yield of approximately 90%, generating a lower amount of reactive power. In the second study, it is shown that in a building cooling system where there was no control of the machines, the installation of magnetic couplings in two pumps resulted in a reduction of 45 kW, about 44%, in the power consumed by the equipment’s, saving 36.000 kWh per year, which proves that this device can be used in energy efficiency projects.