JPH0284090A - Crane deceleration abnormality detection device - Google Patents

Abstract

PURPOSE:To automatically detect the abnormality of deceleration by comparing the change of output frequency from an inverter controlling section at the time of the deceleration of a crane, with a deceleration curve for the input provided previously. CONSTITUTION:By applying a frequency command to an inverter controller 2, the speed of a motor 1 is controlled. At the time of deceleration, by a discharge resistor 3, regenerative energy is discharged. The input of the output frequency signal of the inverter controller 2, to a damping effect discriminating means 4a in a microcomputer 4 is provided, and a deceleration pattern at the time of the deceleration is compared with the deceleration pattern of input provided previously, and when there is a difference between the two patterns, an alarm 5 is worked and a mechanical forcing device 6 is worked.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a deceleration abnormality detection device for an inverter control device for a crane operating an inverter IIl11ml.

An inverter control device for a crane that performs regenerative braking by connecting a discharge resistor for absorbing regenerative energy to the inverter control device is known.

This crane regenerative braking system has a problem in that when the load exceeds the rated value, predetermined deceleration characteristics cannot be obtained due to an incorrect setting of the deceleration characteristics of the inverter control device or a failure of the inverter control unit control device.

0 Means for Solving the above-mentioned Problems In order to solve the above-mentioned problems of the prior art, the present invention detects an abnormality in the deceleration characteristics of a crane, and prevents the crane from hoisting, traversing or traveling when the abnormality occurs. The purpose is to prevent accidents due to an increase in the stopping distance of the motor, and the output frequency signal from the inverter control unit is input and the predetermined deceleration curve is compared with a predetermined deceleration curve stored in advance. A microcomputer is attached to the inverter ItlIJ91 device, which functions as a regenerative braking effect determining means that determines whether the speed characteristics are obtained and outputs a signal when determining that the deceleration is insufficient.

○Example The following description will be made based on the embodiments shown in the drawings.

Referring to FIG. 1, crane hoisting, traversing, or traveling motor 1. Inverter S1m installation'112. Discharge resistance 3
The construction of a part of the crane regenerative braking system is similar to the prior art system.

In carrying out the present invention, a microcomputer (central processing unit) 4 is attached to the inverter control device 2, and an output frequency signal from the inverter [11 device 2] is inputted to the microcomputer 4.
It also outputs an alarm signal to the crane control device 5, and the microcomputer program determines whether or not a predetermined braking effect is present by comparing the output frequency signal with a predetermined deceleration curve stored in advance. When it is determined that the braking effect is insufficient, an alarm signal is outputted and the mechanical braking device 6 is operated to function as a braking effect determining means 4a.

Referring to FIG. 2, the song MP is a microcomputer setting device.

A deceleration curve having desired characteristics is set in advance by a microcomputer program using a recording means or the like.

If the time required for deceleration becomes longer than a predetermined time due to an excessive load, an incorrect setting of the deceleration characteristics of the inverter control device, or a failure of the inverter device, the curve Q in FIG. 2 will result.

If the allowable limit characteristic curve is R for the desired deceleration curve P, then the curve Q indicates insufficient braking. Microcomputer 4
The function of the braking effect determination means 4a determines the above-mentioned insufficient braking and outputs the alarm fi1, and at the same time applies mechanical braking by the mechanically reduced dynamic device W16 to immediately stop the crane.

Note that the curve P can be changed as appropriate by changing the microcomputer program.

○Effects of the Invention The present invention prevents accidents caused by operation exceeding the rating, incorrect setting of the deceleration characteristics of the inverter device, or an increase in the stopping distance of the crane due to failure during crane lifting or traversing/traveling movement work. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing the crane regenerative braking system of the present invention, and FIG. 2 is a graph showing deceleration characteristics. 1...Motor 2...Inverter control device 3...Discharge resistor 4...Microcomputer 4a...Braking effect determination means 5... ...Alarm device 6...Mechanical braking device → Time signal

Claims (1)

[Claims] In a crane that performs regenerative braking by connecting a discharge resistor that absorbs energy for regenerative braking to an inverter control device that controls the motor, the output frequency signal from the inverter control section is input and the predetermined deceleration is set in advance. A microcomputer that functions as a braking effect determining means determines whether a predetermined deceleration characteristic is obtained by comparing the curve with the output frequency signal, and outputs a signal when determining that deceleration is insufficient. A crane deceleration abnormality detection device characterized by being provided with a crane deceleration abnormality detection device.