A detection method for the ascent stall of the hoisting mechanism of the crane

Abstract

The invention discloses a detection method of rising stall of an elevating mechanism in a crane and relate to the technical field of safe protection of cranes. The invention solves a technical problem that a detection method in the prior art is high in fault mis-alarm rate. The method in the invention comprises following steps: performing continuous sampling to rotation rate of a motor when a load is declined during a load lifting process by the elevating mechanism; and calculating a linear speed of the load according to rotation rate sampling data of the motor; calculating an equivalent declining distance of the load according to the linear speed of the load; and then determining whether a rising stall fault exists during an increasing process of the load or not according to the equivalent declining distance of the load. The method is high in detection efficiency and is low in the fault mis-alarm rate and has excellent safe protection effect on the elevating mechanism in the crane.

Description

technical field [0001] The invention relates to a detection method for the ascent stall of a crane lifting mechanism, and belongs to the technical field of crane safety protection. Background technique [0002] For the hoisting mechanism of the crane, when the rated load is hoisted and the motor torque is insufficient due to some reasons (such as insufficient power supply voltage, failure of the speed control device, etc.), the load will fall rapidly under the action of gravity. It is called a load rising stall fault, which can easily lead to accidents, so it is necessary to take protective measures. [0003] However, during the normal lifting process of the crane, when the lifting mechanism starts, the load will often drop slightly first and then start to rise normally due to reasons such as excessive load or occasional voltage fluctuations. This is a normal phenomenon, and the drop of the load at this time is A controlled, rather than a completely uncontrolled fall. [0...

AI Technical Summary

Problems solved by technology

[0003] However, during the normal lifting process of the crane, when the lifting mechanism starts, the load will often drop slightly first and then start to rise normally due to reasons such as excessive load or occasional voltage fluctuations. This is a normal phenomenon, and the drop of the load at this time is A controlled, rather than a completely uncontrolled fall

[0004] Load rise and stall faults are serious faults that must be detected and protected within a short period of time. At present, the load rise and stall fault detection methods for crane lifting mechanisms are all realized by simply judging the motor speed (for example: China's practical The crane stall protection device described in the new patent CN03227441.6), because the motor speed of the lifting mechanism cannot be very high in a short period of time when starting, so when the load drops, it is impossible to effectively distinguish whether the load is by detecting the motor speed. normal fall or uncontrolled fall

Therefore, the existing fault detection method for load rising stall has the defect of high fault false alarm rate. This frequent fault false alarm will easily cause the operator to be unable to identify the real fault, so that the fault will be ignored and cause an accident.

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