Apparatus and process for determining the instantaneous and continuous loads on a lifting mechanism

US5859373A · kind A · utility

Assignee

• Mannesmann AG · DE

Inventors

• Anton Munzebrock · Dortmund, DE
• Eberhard Schroder
• Michael Hulsmann · Herdecke, DE

Key dates

• Filing date: Apr 17, 1997
• Grant date: Jan 12, 1999
• Expiry date: Apr 17, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H02P29/40
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

A process and apparatus for determining a load on a lifting mechanism including a load measuring device and a three-phase induction motor operable for lifting and lowering the load. The effective power consumption of the induction motor is determined by the load measuring device based on a measured current and measured voltage of the induction motor. The measured effective power consumption is then compared with a reference power, which is calculated as the power output of the induction motor driving a nominal load of the lifting mechanism, to calculated an instantaneous load on the lifting mechanism. The inventive apparatus and process advantageously requires no modifications or additions to load carrying parts of a lifting mechanism or carrying gear and provides accurate real time measurement of the load.