SU623803A1 - Emergency protection device for mine hoist lifting motors - Google Patents

Description

The invention relates to the field of automatic control and protection of mine hoisting plants with a DC drive and can be used in the lifting of road-building equipment.

It is known an emergency protection device for lifting motors of mine hoisting installations, containing a current sensor and an actuating element 1. However, such a device is ineffective due to the low accuracy of monitoring changes in the current diagram of a lifting engine, since the current setting value of the relay is higher than the maximum current value of the current diagram of the lifting engine on the corresponding plot. The analysis of accidents at lifting installations showed that the destruction of the trunk reinforcement occurs at currents of the main circuit that are much lower than the current of the set overcurrent relay.

The purpose of the invention is to improve the accuracy of continuous monitoring of current variations in the main circuit of a lifting motor.

This is achieved in that the device is equipped with a motion playback unit, an approximation unit block, a frequency block, a conversion unit, and a comparison device. Moreover, the output of the motion playback unit is connected to the input of the block of approximation nodes, the first output of which is connected to the input of the frequency block, the output of the latter is connected to the first input of the conversion unit, the second input of which is connected to the second output of the block of approximation nodes, , the second input of which is connected to the current sensor,

and the output - with the input of the actuator.

FIG. I shows the block diagram of the device; on fng. 2 - approximated current diagram of the lifting motor. The protection device contains a motion playback unit I, the output of which is connected to the input of a block 2 approximation nodes. The first output of the latter is connected to the input of the frequency block 3, the output of which is connected to the first input of the conversion unit 4. The second input of the conversion unit is connected to the second output of the block of approximation nodes. The output of the conversion unit is connected to the first input of the comparison device 5, the second input of which is connected to the current sensor 6. The output of the comparison device is connected to the input of the actuating element 7.

The operation of the protection device is based on the principle of continuous monitoring of the current J of the main circuit of the lifting motor by comparing the program current diagram specified in the function S of the program current diagram corresponding to the specified operating mode with the actual current diagram of the lifting engine. For convenience, the program current diagram is approximated by straight lines (see Fig. 2j. At each section of the approximation, the rate of change of the current of the lifting motor is assumed constant and determined by the angle of inclination of the linear section to the abscissa axis. The rate of change of current on each section of the approximated the current diagram corresponds to a certain value of the frequency of the pulses entering the counter, the code of which is converted to an analog value. The rate of change of this analog value is determined by the hour . Ota entering the pulse counter Referring to approximate a program of the current diagram, the current rate of change can have positive and negative signs on the approximation of the areas where the velocity is positive, pulses counter act addition, but where negative -. Subtraction.

The motion playback unit 1 is designed to determine the motion parameters of the lifting vessel. It reads the magnetic marks associated with the hoisting rope or hoist mask and converts the pulses obtained by reading. At the output of the motion playback unit, there is a sequence of pulses whose frequency is proportional to the speed of movement of the lifting vessel, and the number to the distance traveled. Block 2 of the fitting nodes, based on the program dialed therein and information about the actual position of the lifting vessel coming from the motion playback unit 1, determines the waypoints that correspond to the fitting nodes. At these points, the block of nodes of approximation carries out

including in block 3 the frequencies of the pulse frequency programmed for this section and sets the pulse counter of the conversion block 4 in accordance with the programm on "addition or" subtraction. The counter code of the conversion unit is converted to an analog value — the current that determines the programmed value of the current diagram. This current enters the comparison device 5, which also receives from the current sensor 6 the actual current value of the lifting motor. If there is a mismatch at any point along the path of the program and the actual value of the currents by an amount more than permissible, the comparison device issues a command to the actuating element 7, which performs an emergency stop of the mine lifting installation.

Claims (1)

1. Kirichok Yu. G. and Chermalykh V.M. The wire of mine hoisting installations of high power. Moscow, “Nedra, 1972, p. 150 ki Well Well Well L7 zm