Mine Hoist Research Articles

State Analysis of Mine Hoist

The objective is to provide a method about equipment condition monitoring and fault diagnosis. The method could indicate equipment operating parameters, working conditions and specific status. We used CDMS system monitoring mine hoist key parts of the vibration velocity, introduces the vibration sensor reasonable decorate, in the time domain analysis of speed amplitude values, in frequency domain speed spectrum analysis, according to the monitoring signal analysis processing results, give the diagnostic conclusions that the gear of second shaft have uniform force, and a little corrosion, peel and eccentric, puts forward that we should strengthen vibration monitoring about the second shaft of speed reducer, Observe reducer wear trend using the iron spectral analysis, Supervise lubricating oil quality, change oil when necessary.

A New Method for Fault Diagnosis of Mine Hoist based on Manifold Learning and Genetic Algorithm Optimized Support Vector Machine

This paper reports a new development based on the manifold learning and intelligent classifier for the nonlinear feature extraction and fault pattern recognition of mine hoists. The wavelet packet was firstly used to extract the statistic characteristics of the hoist vibrations to obtain the original feature space. Then the locally linear embedding (LLE) was employed to learn the underlying nonlinear manifold in the original feature space to select distinct features. Following, the support vector machine (SVM) was applied to the fault pattern recognition. The energy-entropy based genetic algorithm was used to optimize the SVM parameters. The experimental vibration data measured on a mine hoist test rig was used to evaluate the proposed method. The diagnosis results show that the proposed method is efficient for the mine hoist and can increase the detection rate by 2.5% or better when compared with existing diagnosis approaches. Ill. 8, bibl. 10, tabl. 1 (in English; abstracts in English and Lithuanian).DOI: http://dx.doi.org/10.5755/j01.eee.123.7.2385

The Design of Disc Brake for Mine Hoist in Civil Engineering

This article will describe the research status and the features of control system of the disc brakes of mine hoist. The disc brakes consist of body, outer cylinder, cylinder, piston, ring, disc springs, plunger, gate disk and other components. The disc brakes use the pre-load of disc springs to force the piston to move towards the brake disc, push the brake pads out, then the brake pads and drum brake disc contact and resulting in positive pressure, then the formation of friction produce a braking torque. When the brake system loose pads, the cylinder is filled with the pressure oil, which make the piston compresses the disc springs, and promote the brake pads to move back and then left brake disc, remove the braking force. The hydraulic circuit of the braking system chooses two-way parallel oil and four oil cylinder brake. A slip road set up a one-way throttle, making the slip road brake slightly delayed, which will achieve two stage braking and make work more stable. This disc brake is normally closed, which means when the hoist does not work, the brake is in the state of braking to prevent the occurrence of accidents. This brake is safe, reliable and sensitive in action. The materials of brake pads is rigid asbestos plastic, which have stable friction coefficient, good wear resistance, is not sensitive to the aqueous medium and salt spray,it has flexible installation location, and it is easy to use, adjust and maintain.

Friction and wear properties of the composite brake material for mine hoister under different initial velocities

The initial velocity determines the energy input of a braking which affects the tribological performance of brake materials seriously. Aiming at emergency braking conditions of mine hoisters, some tribological experiments and scanning electron microscopy analysis was carried out to reveal its influence on the composite brake materials. It is found that when the initial velocity is increasing, the mean coefficient of friction and its stability coefficient all decreases first then rises and decreases again while the wear rate rises continually. By contrast, it rises slowly at a low velocity, fast at a middle velocity and slowly again at a high velocity. It is concluded that some tribological related films generated by braking load and heat oxidization weaken the friction at the beginning of braking. Its friction weakening influence appears more obviously under a braking with a lower initial velocity. However, the films may also help to reduce braking wear. As the impacting frequency and velocity between surface asperities are all affected by the initial velocity, a bigger initial velocity will cause a worse wear. For short braking time, only a thin material on the surface is destroyed. The main wear modality of the pairs may be mechanical wear: cutting wear on the brake disc, fatigue and grooving wear on the brake shoe.

Influence of braking pressure on tribological performance of non‐asbestos brake shoe for mine hoister during emergency braking

PurposeThe purpose of this paper is to describe some tribological experiments which were executed to find the influence of braking pressure on tribological performance of non‐asbestos brake shoe used in mine hoister during its emergency braking.Design/methodology/approachThe WSM‐3 non‐asbestos brake shoe, which has been widely used in mine hoister, was selected as experimental material. Some tribological experiments of the brake shoe sliding on 16Mn steel were investigated on the X‐DM friction tester by simulating of emergency braking conditions of mine hoister. Three kinds of tribological indexes: friction coefficient, stability coefficient of friction coefficient, and wear rate were considered to score the tribological performance and the morphology of worn surfaces were observed through the S‐3000N scanning electron microscopy (SEM) to explore the tribological mechanisms.FindingsIt was found first, that the instant friction coefficient is not constant during emergency braking. After a short climbing period, it rises gradually to steady value. Second, with the increasing of braking pressure, the mean friction coefficient rises first then falls, while its stability coefficient falls gradually. The wear rate rises continuously with the braking pressure increasing. Also, the rising velocity of wear rate at high pressure is higher than it is at low pressure. Third, the instant surface temperature rises first then falls during braking and the mean surface temperature rises continuously with the braking pressure increasing.Originality/valueIt is found that the increasing of braking pressure within a certain range is helpful for achieving a high friction coefficient and a steady wear rate. But too high pressure will cause contrarily the falling of frictional performance and serious of wear performance. So it is not reliable to rise the braking pressure without limited during emergency braking.

Research on Safety Monitoring System of Mine Hoist Based on VB

According to the possible problems of mine hoist in use, this paper puts forward a set of safety monitoring system. Due to the mechanical failure is the main failure types of mine hoist, the safety monitoring system proposed is mainly aimed at the mechanical failure. Through the monitoring of brake oil pressure, spring pressure, brake shoe displacement and other related parameters, mine hoist can be operated safely and stably. PIC microcontroller chip is adopted in this monitoring system to monitor spot data, and VB is used for programming software of upper machine, to analyze, and memorize data.

New Junction Temperature Balancing Method for a Three Level Active NPC Converter

SummaryThe three-level Neutral Point Clamped Voltage Source Converter (3L-NPC VSC, 3L-ANPC VSC) has many attractive features like its high reliability and availability. Nowadays, this technology is mature and can be found in several industrial applications [1], [2]. Some common applications are pumps, fans, compressors, mixers, extruders, crushers, rolling mills, mine hoist drives and excavators.The three-level Active NPC VSC (3L-ANPC VSC) was introduced in 2001 to overcome the drawbacks of the conventional 3L-NPC VSC [3]. The 3L-ANPC VSC includes additionally active switches parallel to the NPC diodes for clamping the neutral tap of the converter. It features 3 extra switch states in contrast to the conventional 3L-NPC VSC, which enable the possibility to reduce the temperature imbalance and/or to increase the output frequency or the converter power. In order to use the potential of the 3L-ANPC VSC and to balance the losses among the semiconductors, the implementation of a temperature balancing strategy is necessary [4] and [5].The medium voltage 3L-ANPC VSC is especially advantageous in the following applications:– High power applications, where the required output power cannot be archived without a serial/parallel connection of devices.– Medium voltage converters, where the switching frequency should be increased without decreasing the converter power (e.g. applications which require a sine filter or high speed applications).– Applications where the nominal converter current is required at low modulation index and low fundamental frequencies (e.g. zero speed operating points, hot and cold rolling mill applications, converters for doubly fed induction generators, etc.).The starting point for the derivation of the new balancing algorithm was the Active Loss Balancing (ALB) system, which is reported in [4] and [5]. The new temperature balancing scheme profits from the features of Predictive Control [6] in order to precalculate the conduction and the switching losses and finally the temperature of each semiconductor up to the future commutation to the zero state, i.e. over the next period of the switching frequency. The precalculated maximal junction temperature will be used for the control strategy in order to determine the optimal switch state to be applied.Some additional features of the new balancing algorithm with respect to the ALB algorithm are: consideration of the conduction losses fed into the balancing algorithm, regard of the temperature ripple between two consecutive commutations and the use of a control criteria (cost function) in the selection of the zero state [6]. The algorithm is implemented in Matlab and compared with the 3L-NPC VSC using experimental data of a 4.5 kV Press-pack IGBT and Diode for the calculation of the losses. The comparison shows a potential to increase the output power of the 3L-ANPC VSC.

Wavelets applied to early fault analysis of hoist gear box

Using wavelets, the vibration signal of a certain mine hoist gear box was analyzed. By multiple comparison analysis, the rational wavelet basis function was determined. Fault characteristic frequencies of hoist gear box were identified. The research indicates that the hoist’s fault information is non-stationary, and non-stationary signal is clearly extracted by using db20 wavelet as basis function. The db20 wavelet is the proper wavelet base for vibration signal analysis of the hoist gear box.

Wear Modalities and Mechanisms of the Mining Non-asbestos Composite Brake Material

The mining brake material is generally made of composite materials and its wear has important influences on the braking performance of disc brakes. In order to improve the braking reliability of mine hoisters, this paper did some tribological investigations on the mining brake material to reveal its wear modalities and mechanisms. The mining non-asbestos brake shoe and 16Mn steel were selected as braking pairs and tested on a pad-on-disc friction tester. And a SEM was used to observe the worn surface of the brake shoe. It is shown that the non-asbestos brake material has mainly five wear modalities: adhesive wear, abrasive wear, cutting wear, fatigue wear and high heat wear. At the front period of a single braking the wear modality is mainly composed of some light mechanical wear such as abrasive, cutting and point adhesive. With the temperature rising at the back period it transforms to some heavy mechanical wear such as piece adhesive and fatigue. While in several repeated brakings once the surface temperature rises beyond the thermal-decomposition point of the bonding material, the strong destructive high heat wear takes leading roles on the surface. And a phenomenon called friction catastrophe (FC) occurs easily, which as a result causes a braking failure. It is considered that the friction heat has important influences on the wear modalities of the brake material. And the reduction of friction heat must be an effective technical method for decreasing wear and avoiding braking failures.

Application of PLC in Mine Hoist System

The control strategy for hoist system based on PLC was proposed in this paper to mend the control shortcomings in the traditional system applying relay logic control circuits. In this paper the hoist structure was analyzed, and the PLC control system realization in hardware and software was introduced too. The control method improves the maintainability and the flexibility of the elevator, extending the using life, and the ideal control effect can be attained. The Practical application showed that this control system has high efficiency, better maintainability and reliability, at the same time, reduce mine hoist system cost .it can be easier to complete more complicate tasks which the traditional control system can not achieve.

Clean Mining Technology of Waste Not Discharged From Coal Mine

In order to solve the problem of heaping waste in aboveground, a cleanly mining technique of waste not discharged from coal mine was proposed. It includes two key points as follows: one is waste separation underground; the other is mining technique with preset packing body of waste without coal pillars. After the waste from the coal mining face had been separated out, the waste was used to preset packing body of waste. It is able to decrease stress of mine hoisting. The technique has been successfully used in Gaozhuang Coal Mine.

Hoist Lubricating Oil Pressure and Liquid Level Detection

This article describes the structure, working principle and technical parameters of the lubricant oil pressure and liquid level indicating alarm system of the mine hoist. In order to send signals to the main control room displaying pressure and liquid level， the use of digital circuit-designed smart modular pressure transmitter, level transmitter, with the light beam warning indicator, display the fluid pressure and fluid level signal in the main control room, the limit alarm, and the upper and lower limit settings.

Effect of various kinematic parameters of mine hoist on fretting parameters of hoisting rope and a new fretting fatigue test apparatus of steel wires

The effect of various kinematic parameters of mine hoist on fretting parameters of the hoisting rope was investigated and a new fretting fatigue test apparatus was designed. A simulation model of the rope tension was presented to examine the role of various kinematic parameters on the rope tension and tension amplitude during lifting. Ranges of fretting parameters of the rope during lifting with different kinematic parameters were determined. The results show that different kinematic parameters induce different modal shapes of the vibrating systems during lifting, which results in distinct ranges of fretting parameters of the rope.

Study on PROFIBUS-DP Field Bus in Mine Hoists Control System

Aiming at the disadvantages of conventional relays in control of mine hoists, this article induces application of full digital DC speed adjusting device based on PROFIBUS-DP field bus. This article gives the control system hardware configuration and software design. This design can make mine hoists perform stably and safely, fully meeting the requirements of modern mining hoists system to upgrade.

Modeling and Analysis of Harmonic in the Mine Hoist Cnverter Based on Double Closed-Loop Control

In the process of converter driving mine hoist, the output voltage waveform of the inverter is distorted. A novel feedback control method based on the filter inductor current inside loop and voltage is developed in this study. The transfer function model of the two closed-loop control is builded. Parameters of the PID controller are determined through theoretical calculation after analysis of the impact the controller parameters on system. The simulation results show that the output waveform is good and the THD(Total Harmonic Distortion) values is small.

The Study on Mechanical Reliability Design Method and Its Application

Based on the reliability test and statistical analysis of the failure data, the basic task of mechanical reliability design is to propose mathematical-mechanical models and methods for engineering practice. In this way the working state and life of the mechanical product under the prescriptive working condition can be predicted in the design stage. The connotation and development of mechanical reliability-based design is expounded by integrating modern mathematical-mechanical theories. A series of theories and approaches, such as the mechanical reliability-based design, dynamic reliability-based design, reliability-based optimization design, reliability-based sensitivity design, reliability-based robust design, are explained clearly and systematically. Based on characteristics of mechanical reliability design, as well as study on reliability design of mine hoist, taking mine hoist spindle bearing as example, this paper discusses the application of reliability design in mine hoist design.

Study on the Influence of the Temperature Rise and Frictional Coefficient of Brake Shoe on Braking of Wind Turbine

The value of brake friction coefficient have to do with temperature rises、speed、press and the influence of temperature rise is most large.Because high speed mine hoist come into being high temperature in apply the brake，it affect friction coefficient and capability of apply the brake system. therefore，unfold study brake temperature rise and friction coefficient forecast is very importance meaning.Because ANN can reflect non-line relation of input and output，this paper puts forward description mapping relation and effect to apply the brake safety of with temperature rises、speed、press and the influence.

Thermo-stress coupling field of friction lining during high-speed slide of wire rope in a mine friction-drive hoist

In order to seek the intrinsic reason for the serious high-speed slide accident in a mine hoist, the thermo-stress coupling field of friction lining was studied during the high-speed slide. First, the helical contact characteristics were analysed. Subsequently, the thermomechanical properties and the dynamic coefficient of linear expansion were studied, and the thermomechanical constitutive relation was obtained. Then, the theoretical model of thermo-stress was established with the consideration of the helical contact characteristics and the thermomechanical constitutive relation. Also, the numerical simulation was performed by the finite element analysis. Finally, the experiment was carried out on a friction tester. It is found that the temperature is the highest at the contact zone II and the friction heat focuses on the contact surface layer. The variation frequency of the stress is 6.98 Hz at 0.5 m/s. Besides, the catastrophe for the strain and coefficient of friction occurs at 3 m/s. The thermo-stress concentration occurs at contact zone II. The experiment results agree with the simulation ones, which validates the theoretical model of thermo-stress.

Analysis of Reliability for Hoist Main Control System Based on Markov Process

A reliability mathematical model of the hoist control system based on Markov process was developed and a formula of availability and reliability of the system was derived. At the same time a redundancy-based technology was introduced to improve the reliability of mine hoist control system according to the special requirements of safety and reliability. A new way of thinking is provided to further study the reliability of similar control system through the reliability study of hoist control system.

The Hoist of Mine Improvement and Design of Brake System Study

The field of mine hoist in the coal mine has an important role, its relationship with the safe operation of coal mine production safety and the lives of many miners. This article of mine hoist began to study the current situation, put forward specific measures for improvement. And the introduction of PLC control system to improve the performance of mine hoist. In this paper, the specific principles of experimental program with the specific design, the study proved of great economic and practical significance.