Propeller fan induction motors for ventilating livestock buildings 1. Mathematical prediction of performance

Abstract

The performance of intensively housed livestock is dependent upon good control of environmental conditions. To achieve these conditions reliable ventilation equipment is required. Ventilation fans which consists of an air impeller driven by an induction motor are commonly used in livestock buildings. A mathematical model to predict the performance of single-phase capacitor start and capacitor run induction motors with transformer or triac speed control has been developed using the unified theory of electrical machines. The performance of three-phase and Steinmetz-wound induction motors can also be predicted with transformer speed control. Good agreement was obtained between predicted and measured values of motor performance factors including r.m.s. voltage in the main winding, conduction angle, total current, current in the main winding and power input.