Transient Torque Produced in Main Shaft of Electric Hoist During Motor Start-Up and Emergency Brake Operations

Abstract

The purpose of this study is to clarify the generation mechanism of the transient torque produced in the main shaft of an electric hoist. A mathematical model with three degrees of freedom is proposed for the transient motion analysis of an electric hoist when lifting a weight and application of an emergency brake. A technique is developed for measuring the transient torque of a main shaft and the transient tension of a wire rope. Comparing the theoretical results with the experimental results, the generation mechanism of the transient torque produced in the main shaft of the electric hoist is clarified. The effects of the torsional stiffness and rotating speed of the main shaft, and the emergency brake torque on the transient torque produced in the main shaft are discussed. Moreover, dynamic load factors for the wire rope are also discussed.