A control system for controlling a three-phase alternating current brake by a single-phase power supply on a crown block

Abstract

The application discloses a control system of a three-phase alternating-current brake controlled by a single-phase power supply on a crown block, and relates to crown block control technology. The control system comprises an uninterruptible power supply, a frequency converter and a control module. The uninterruptible power supply is used for outputting 220V alternating-current power when the crown block is powered off; the frequency converter is used for receiving 220V alternating-current power output by the uninterruptible power supply and outputting 380V three-phase alternating-current power to a control loop of a hoist brake; the control module is used for collecting an electric quantity value reserved by the uninterruptible power supply; when the electric quantity value is lower than a set electric quantity threshold value, a trigger signal for forcibly starting the hoist brake is preset; then the lowest relative height of a heavy object is collected, and when the lowest relative height of the heavy object is greater than a set suspension safety height, the trigger signal is output to forcibly start the hoist brake to release the brake of the hoist machine and lower the heavy object. The application can safely and quickly electrically control the hoist brake when the crown block is powered off, lower the heavy object to a safe position, and effectively prevent the occurrence of equipment and personal safety accidents.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crown block control, more particularly to a control system for controlling a three-phase AC brake by a single-phase power supply on a crown block. BACKGROUND

[0002] In a steel enterprise, a crown block is a common large equipment, which realizes the lifting of heavy objects such as a steel ladle, a billet and a steel product by a hoist, and realizes the carrying and moving of the heavy objects by a moving system of the crown block. In order to position the lifted heavy objects in the air, a hoist brake is needed to realize the braking of the hoist. For the existing crown block, the hoist brake is mostly a three-phase AC 380V electric hydraulic brake.

[0003] When the crown block is powered off, the three-phase AC 380V power supply cannot be provided in a short time, which not only makes the crown block unable to move, but also makes the hoist brake unable to operate, thereby greatly affecting the production. Moreover, if the heavy object lifted by the crown block is above a passageway, a great safety hazard exists. In this case, only the crown block operator manually releases the hoist brake. However, the manual release of the hoist brake is difficult to operate and has low release precision, thereby greatly increasing the danger of the site. SUMMARY

[0004] The present application aims at solving the problems of the prior art, and provides a control system for controlling a three-phase AC brake by a single-phase power supply on a crown block, thereby solving the problem of great danger of manually releasing the hoist brake when the crown block is powered off.

[0005] The control system for controlling a three-phase AC brake by a single-phase power supply on a crown block comprises,

[0006] An uninterruptible power supply is used to reserve electric energy, so as to output 220V AC power when the crown block is powered off;

[0007] A frequency converter is used to receive the 220V AC power output by the uninterruptible power supply, and output 380V three-phase AC power to a control loop of the hoist brake;

[0008] A control module is installed in a cockpit of the crown block, and is used to collect an electric quantity value of the reserved electric quantity of the uninterruptible power supply, judge whether the electric quantity value is lower than a set electric quantity threshold, preset a trigger signal for forcibly starting the hoist brake when the electric quantity value is lower than the set electric quantity threshold, collect a lowest relative height of the heavy object, and output the trigger signal to forcibly start the hoist brake to release the braking of the hoist and make the heavy object suspended by the crown block to descend to a set suspension safety height when the lowest relative height of the heavy object is greater than the set suspension safety height.

[0009] The uninterrupted power supply is an AC uninterrupted power supply with single-in and single-out.

[0010] The control module comprises a first distance measuring module, a second distance measuring module and a controller.

[0011] The first distance measuring module is installed on the cantilever of the crown block and above the lifting tool of the crown block; the second distance measuring module is installed on the cantilever of the crown block and the testing direction of the testing end of the second distance measuring module does not interfere with the lifting tool and the weight suspended by the lifting tool; the output ends of the first distance measuring module and the second distance measuring module are electrically connected with two signal acquisition ends of the controller respectively.

[0012] The first distance measuring module is an ultrasonic distance measuring module; the second distance measuring module is a laser distance measuring module.

[0013] The control module comprises an electric quantity display unit, which is used for displaying the electric quantity value information when the driver is in the driver cabin of the crown block.

[0014] The electric quantity display unit comprises a pressure sensor and a plurality of indicator lights; the indicator lights are installed in the driver cabin of the crown block, and the pressure sensor is installed in the seat of the driver cabin; the indicator lights and the pressure sensor are electrically connected with the output end of the controller.

[0015] The electric quantity display unit further comprises an audible and visual alarm; the audible and visual alarm is installed in the driver cabin of the crown block; the audible and visual alarm is electrically connected with the output end of the controller, so that when the electric quantity value collected by the controller is lower than a preset minimum operable electric quantity value, the controller controls the audible and visual alarm to be started.

[0016] Advantages

[0017] The present application has the advantages that:

[0018] 1. The uninterrupted power supply and the frequency converter are added to the original power system of the crown block, so that the control circuit of the hoist brake can be powered by the uninterrupted power supply and the frequency converter in the case of power failure, and the driver of the crown block can safely and quickly control the hoist brake to lower the weight to a safe position, effectively preventing the occurrence of equipment and personal safety accidents.

[0019] 2. When the electric quantity of the UPS is low, the height of the suspended weight is lowered by forced means, which can effectively prevent the problem of great loss caused by the weight falling from a too high position due to the failure of the hoist brake in the case that the power supply is powered off and the UPS has no electric energy output. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 It is a control system working process diagram of the present application.

[0021] Fig. 2 The control system structure of the application is modularized. DETAILED DESCRIPTION

[0022] The application will be further described below in conjunction with the embodiments, but does not constitute any limitation to the application, and any limited modification made by anyone within the scope of the claims of the application is still within the scope of the claims of the application.

[0023] Referring to Figs. 1-2 The control system of the application for controlling the three-phase AC brake by the single-phase power supply on the overhead crane comprises an uninterrupted power supply (UPS), a frequency converter and a control module. The UPS adopted in the embodiment is an AC uninterrupted power supply with single input and single output, which is used to reserve power to output 220V AC power when the overhead crane is powered off. The main reason for adopting the UPS with single input and single output is that the 220V AC power output can be used to supply power to the control module and emergency equipment in the overhead crane which adopt single-phase power, and the 220V AC power can also be input into the frequency converter to convert the 220V AC power into 380V three-phase AC power, and the 380V three-phase AC power is delivered to the control circuit of the hoist brake to realize power supply for the hoist brake in the power-off state.

[0024] The specific working process is as follows: when the external power supply of the overhead crane is normal, the external power supply is used to supply power to the uninterrupted power supply with single input and single output. While the uninterrupted power supply is charging, the external power supply also supplies power to the frequency converter through the uninterrupted power supply, and the 380V three-phase AC power output from the frequency converter is delivered to the control circuit of the hoist brake to realize normal power supply. At this time, the crane driver can realize the operation of the hoist brake through the buttons of the control circuit of the hoist brake. When the overhead crane is suddenly powered off, i.e. the external power supply is stopped, at this time, the UPS itself stores a certain capacity of power, which can release 220V AC power to the frequency converter, and the frequency converter can still deliver the power to the control circuit of the hoist brake, and the crane driver can still realize the operation of the hoist brake through the buttons of the control circuit of the hoist brake to restore the control of the hoist brake.

[0025] The control module comprises a first distance measuring module, a second distance measuring module, a controller and a power display unit. The controller can adopt PLC.

[0026] The power display unit is used to display the power value information when the driver is in the cockpit of the overhead crane. The power display unit comprises a pressure sensor, an audible and visual alarm and a plurality of indicator lights. The indicator lights and the audible and visual alarm are installed in the cockpit of the overhead crane, and the pressure sensor is installed in the seat of the cockpit. The indicator lights, the audible and visual alarm and the pressure sensor are electrically connected with the output end of the controller.

[0027] When the driver sits on the seat, the pressure sensor sends a signal to the PLC. After the PLC receives the pressure signal, the acquired electric quantity value information is displayed through the indicator light and the audible and visual alarm, which can reduce the consumption of UPS electric quantity. Specifically, when the pressure sensor outputs the pressure signal to the PLC, the PLC collects the electric quantity value of the UPS reserve electric energy, and compares the collected electric quantity value with the preset electric quantity range to determine the electric quantity range where the electric quantity value is located, and controls the indicator light corresponding to the electric quantity range where the electric quantity value is located to be lit.

[0028] For the collection of the battery electric quantity in the UPS, the embodiment is realized by the PLC. The PLC can read the information about the battery electric quantity in the internal program of the UPS directly, or collect the electric quantity value of the battery in the UPS through the existing technology of collecting the battery electric quantity. Since the present application does not improve the technology of collecting the battery electric quantity in the UPS by the PLC, it will not be discussed further herein.

[0029] After the PLC collects the electric quantity value, the corresponding indicator light can be lit according to the percentage of the electric quantity to remind the driver of the current electric quantity of the UPS. For example, five indicator lights are used, and each indicator light represents 20% of the electric quantity. If the current electric quantity is 60%, the PLC can control three indicator lights to be lit.

[0030] The function of the audible and visual alarm is to remind the driver to operate the related operation button of the hoist brake as soon as possible when the electric quantity value collected by the controller is lower than a preset minimum operable electric quantity value (such as 40%), so as to quickly lower the heavy object to the ground and prevent the problem that the heavy object is still suspended in the air after the UPS electric energy is consumed.

[0031] In order to prevent the problem that the heavy object is still suspended in the air after the UPS electric energy is consumed, which causes a high safety risk, the present application solves the problem by the following technical means.

[0032] The first distance measuring module is installed on the cantilever of the crown block and above the lifting device of the crown block. It is mainly used to measure the distance between the heavy object and the cantilever of the crown block. In order to achieve accurate measurement, the first distance measuring module can adopt multiple installation arrangements. When collecting the output data of multiple first distance measuring modules, a maximum error percentage can be set in the PLC. First, the mean value of all collected measurement data is obtained. Then, the difference between each measurement data and the first mean value is obtained. The percentage of the data difference and the first mean value is compared with the maximum error percentage. The measurement data corresponding to the maximum error percentage is removed. After error removal processing of all measurement data, the average value of the remaining measurement data is taken as the distance between the heavy object and the cantilever of the crown block, to ensure the accuracy and effectiveness of the measurement data. In addition, considering that the heavy object may be a steel ladle with a high temperature, the first distance measuring module is preferably an ultrasonic distance measuring module, which can reduce the influence of temperature on the distance measuring medium and ensure measurement accuracy.

[0033] The second distance measuring module is installed on the cantilever of the crown block, and the test direction of the test end of the second distance measuring module does not interfere with the lifting device and the heavy object suspended by the lifting device. That is, the second distance measuring module measures the distance between the cantilever and the object closest to the heavy object below the heavy object. For example, if the ground is below the heavy object, the second distance measuring module measures the distance between the cantilever and the ground. If there are vehicles or accumulations below the heavy object, the second distance measuring module measures the distance between the cantilever and these objects.

[0034] The second distance measuring module can also adopt multiple installation arrangements. Considering the unevenness of the surface of the vehicles or accumulations, the PLC of the present embodiment can directly take the average value of the measurement data of multiple second distance measuring modules. The second distance measuring module adopts a laser distance measuring module. Since the laser beam generated by the laser distance measuring module is relatively thin, it can effectively prevent the problem of inaccurate distance measurement caused by the heavy object being too close to the trajectory of the laser beam.

[0035] In addition, in order to prevent the problem of measurement data error caused by the heavy object blocking the laser beam, the PLC of the present embodiment compares the measurement data of all second distance measuring modules with the average value of the measurement data of all first distance measuring modules. If part of the measurement data of the second distance measuring module, for example, not more than 1 / 3 of the measurement data, is within ±10% of the average value, it indicates that the laser beam of the second distance measuring module corresponding to the measurement data may be irradiated on the heavy object, so this part of the measurement data can be removed to ensure the accuracy of the data.

[0036] The PLC is installed in the driver cabin of the crown block, and is mainly used to determine whether the UPS power value is lower than the set power threshold (for example, the power threshold is set to 20% of the power). When the power value is lower than the set power threshold, a trigger signal for forcibly starting the hoist brake is preset. Then the lowest relative height of the heavy object is collected, that is, the difference between the average value of the effective measurement data obtained by the second distance measuring module and the average value of the effective measurement data obtained by the first distance measuring module. When the lowest relative height of the heavy object is greater than the set suspension safety height, a trigger signal is output to forcibly start the hoist brake to release the brake of the hoist, and the heavy object suspended by the crown block is lowered to the set suspension safety height.

[0037] In the embodiment, when the UPS power is low, the suspension height of the heavy object is lowered by a forced manner, which can effectively prevent the heavy object from falling from a too high position to cause a large loss due to the power supply being powered off and the hoist brake malfunctioning when the UPS has no power output.

[0038] The above only describes the preferred embodiments of the present application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present application, which will not affect the effect of the present application and the practicality of the patent.

Claims

1. A control system for a three-phase AC brake controlled by a single-phase power supply on an overhead crane, characterized in that, include, An uninterruptible power supply (UPS) is used to store electrical energy so that it can output 220V AC power when the overhead crane loses power. The frequency converter is used to receive the 220V AC power output from the uninterruptible power supply and output 380V three-phase AC power to the control circuit of the hoist brake. The control module is installed in the cab of the overhead crane; it is used to collect the power value of the uninterruptible power supply's stored power, determine whether the power value is lower than a set power threshold; when the power value is lower than the set power threshold, it presets a trigger signal to forcefully start the winch brake; then it collects the lowest relative height of the load, and when the lowest relative height of the load is greater than the set suspension safety height, it outputs the trigger signal to forcefully start the winch brake to release the brake on the winch, and lower the load suspended by the overhead crane to the set suspension safety height; The control module includes a first ranging module, a second ranging module, and a controller; The first ranging module is installed on the cantilever of the overhead crane and is located above the crane's lifting device; the second ranging module is installed on the cantilever of the overhead crane, and there is no interference between the test direction of its test end and the lifting device and the weight suspended by the lifting device; the output ends of the first ranging module and the second ranging module are electrically connected to the two signal acquisition ends of the controller, respectively.

2. The control system for a single-phase power supply controlling a three-phase AC brake on an overhead crane according to claim 1, characterized in that, The uninterruptible power supply is a single-input, single-output AC uninterruptible power supply.

3. The control system for a single-phase power supply controlling a three-phase AC brake on an overhead crane according to claim 1, characterized in that, The first ranging module uses an ultrasonic ranging module; the second ranging module uses a laser ranging module.

4. The control system for a single-phase power supply controlling a three-phase AC brake on an overhead crane according to claim 1, characterized in that, The control module includes a power display unit, used to display the power value information when there is a driver in the cockpit of the crane.

5. The control system for a single-phase power supply controlling a three-phase AC brake on an overhead crane according to claim 4, characterized in that, The power display unit includes a pressure sensor and several indicator lights; the indicator lights are installed in the crane's cab, and the pressure sensor is installed in the cab seat; both the indicator lights and the pressure sensor are electrically connected to the output of the controller.

6. The control system for a single-phase power supply controlling a three-phase AC brake on an overhead crane according to claim 5, characterized in that, The power display unit also includes an audible and visual alarm; the audible and visual alarm is installed in the crane's cab; the audible and visual alarm is electrically connected to the output of the controller so that when the power value collected by the controller is lower than a preset minimum operable power value, the controller controls the activation of the audible and visual alarm.

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