On the Immunity of a Crane Safety Equipment

The paper deals with problems related to electromagnetic compatibility occurring at a safety tool for cranes used as a safety component of the crane designed to automatically interrupt the operation of the lifting gear, when rated loads and respectively load moments are exceeded. Immunity to electromagnetic disturbances is approached. The above mentioned equipment is presented, paying a special attention to the places where problems related to electromagnetic susceptibility can occur (e.g. the supplying source). The operating modalities of the equipment under test are presented along with the criteria to be accomplished by the equipment. The accomplished immunity tests (performed according to the standards in force) are described and analyzed. They address the electrostatic discharges, the immunity to conducted radio-frequency electromagnetic field and the surge immunity. Tests results after the applying of anti-perturbative measures are presented. Details on some of the measurements are included in the paper.