Study of the Effect of Throttling on the Success of Starting a Line-Start Permanent Magnet Motor Driving a Centrifugal Fan

Abstract

Direct-on-line synchronous motors are a good alternative to induction motors in fluid machinery drives due to their greater energy efficiency but have the significant disadvantage of limiting the maximum moment of inertia of the loading mechanism to ensure their successful and reliable start-up. This disadvantage is critical in centrifugal fans with a massive steel impeller. In this article, using a mathematical model, the dynamics of starting and synchronizing a permanent magnet synchronous motor fed directly from the mains as part of a fan drive are studied. The simulation results show the possibility of increasing the maximum moment of inertia of the load at the successful start-up of a direct-on-line synchronous motor by adjusting the hydraulic part of the fan pipeline by means of throttling. The conclusions of this paper can be used when selecting an electric motor to drive industrial fans and can contribute to wider use of energy-efficient synchronous motors with direct start-up from the mains.