Design method for overwind arrestors

Abstract

The relentless drive for safer winding systems has seen more serious consideration given to arresting systems in recent years. Design criteria have been debated. Arrestors are roughly selected based on average retardation rates and energy absorption capacity. Standards Australia sets criteria for design of arrestors that go beyond average retardation rates and energy absorption but provide little design guidance. Although sophisticated dynamic simulation methods have illuminated the true dynamic behavior of arresting systems, they are not available to most designers. Based on approximate dynamic models of conveyance arresting, this paper addresses the opportunity to equip the designer with computational tools that go beyond mere energy considerations but stop short of full dynamic simulation. Methods are presented to estimate the conveyance displacement, velocity, and acceleration in a headframe or shaft bottom arrestor. Equations for the approximate calculation of head rope forces during headframe arrest are included. A model of crash beam impact results in an approach to assessing whether head ropes fail if this occurs.