Influence of capacity limiter operation with tripping thresholds on the overhead cranes safety

Abstract

The analysis of the operating algorithm of the existing lifting capacity limiters is given. The considered approach is to disconnect the hoisting mechanism when load limit value is reached. For a number of cranes, characterized by relatively high values of dynamism coefficients, it is shown that it is impossible to meet the safety requirements when using the algorithm with a single threshold.

The purpose of the study was to evaluate the effect of the load limiter, which uses an algorithm of operation with intermediate thresholds of operation, on the safety status of overhead cranes.

The algorithm of the capacity limiter operation with intermediate thresholds is described. The possibility of achieving the requirements of regulatory and technical documentation relating to the protection of the crane from overloading, based on the algorithm of the capacity limiter with intermediate thresholds is confirmed experimentally.

On the experimental basis, the effect of the studied capacity limiter algorithm on the dynamism coefficient is examined. It is shown that while lifting near-nominal loads (85–125% of nominal weight) the peak dynamic load on the crane is reduced by 9.2–29.4%.

It is concluded that the algorithm with intermediate thresholds is applicable to meet the requirements for protecting the crane from overloads. The reduction of dynamic loads during the lifting of near-nominal loads, which increases the lifetime of the crane components, is evaluated.