Development of the electrical drive of the 2LT-80 tape conveyer

Contents

TASK

INTRODUCTION

Climatic operating conditions and selection of the degree of protection of electrical equipment

Calculation and selection of mechanical gear kinematics elements

2.1 Calculation and selection of conveyor belt

2.2 Calculation and selection of roller diameter and distance between

rolikoopor

2.3. Calculation and selection of drum diameter

2.4. Gearbox calculation and selection

Calculation of belt resistance forces on conveyor sections

4. Calculation of electric drive

4.1. Select Motor by Catalog

4.2. Calculation of the required rigidity of the mechanical characteristic of the second engine

4.3. Calculation of dynamic loads of conveyor drive in emergency start mode fully loaded

4.4. Check of selected engines by heating and overload capacity

5. Analysis of possible variants of power channel of conveyor electric drive

6. Structural diagram of electric drive

6.1. Frequency converters of "UNIVERSAL" series

6.2. Advantages of using electric drives based on IF "UNIVERSAL"

7. Transient Simulation

8. Calculation of asynchronous short-circuited motor characteristics

8.1. When controlled by frequency converter with voltage inverter

8.2. At control from frequency converter with current inverter

9. Description of electrical circuit operation

9.1. Functions performed by the schema

10. Power supply

10.1. Selection of power supply system

10.2. Calculation of power supply of the treatment area

mine "Moscow Region"

10.2.1. Selection of district power transformer

10.2.2. Selection of cable network sections by heating

10.2.3. Calculation of section network by voltage loss at normal operation mode

10.2.4. Check of the area network for voltage fluctuations during start-up mode

10.3. Protection of cables and electrical equipment installed in underground workings

11. Automated Conveyor Accessory

11.1. Tape Release Control

11.2. Tape slip and break control

11.3. Registration of transported goods

12. Occupational and environmental protection

12.1. Analysis of hazardous and harmful factors

12.2. Development of devices for cleaning ventilation and industrial emissions from gases and dust

12.3. Calculation and design of grounding device

12.4. Fire safety

12.5. Environmental protection

13. Technical and economic indicators

LIST OF LITERATURE

Application

Introduction

The desire to increase the productivity and quality of products, create conditions for complex automation leads to the continuous expansion of a large class of continuous units, ensuring the continuity of the process by combining individual operations in one line. This class of aggregates includes processing lines for polymer products: extrusion machines and continuous vulcanization lines for coating the core of cable or wires, cord lines tread and auto-chamber units, lines for the production of films and coating them, units for the production of sheet and pipes from plastics and a number of other mechanisms.

Optimization of the manufacturing process of the product on the considered units is carried out in two directions. The first is related to the improvement of the equipment of the lines and its operation. The second direction involves the use of automatic control systems for electric drives with stabilization of the main coordinates that determine the quality of the product. Such coordinates primarily include the speed of movement and tension of the workpiece, its output dimensions .

As technological processes intensify, the presence of elastic links in the mechanical part of the electric drive has an increasing influence on the dynamics of electric drives and product quality.

Climatic operating conditions and selection of the degree of protection of electrical equipment

The mine "Moscow Region" OJSC "Tulaugol" is located in the Venevsky district of the Tula region, 25 km south of the district center of Venev, 7 km north of the city of NovDonbass.

Commissioned on December 28, 1974. The mine field is located on the East Gryzlovskoye field.

The coal bed has a complex structure, the gypsometry of the bed is slightly wavy .

The ash content of the mined rock mass, taking into account the volumetric weight of coal and rock layers, ranges from 3744%.

The field of the mine is watered, the coefficient of water availability is 10m3/t.

The mine is not dangerous for gas and dust, the relative gas abundance is 1.72 m3/t.

Coal is delivered by 1L100K and 2LT80 belt conveyors.

The pipeline symbol is as follows:

2 - conveyor size;

L - tape;

T - telescopic;

80 is the width of the tape in cm.

Conveyor is intended for transportation of coal (rock mass) in coal and shale mines.

Conveyor 2LT80, 2LT80U is installed in workings with inclination angles from minus 10 to plus 10 degrees.

Conveyor delivery length - 100m.

Atmosphere of type 1 as per GOST 15150 at dust content of air not more than 200 mg/m3 .

Relative humidity at temperature 250С, not more than 98%.

Temperate macroclimatic area (version Y)

Placement category 5 as per GOST 1515069 height above sea level is not more than - 1000 m.

Supply voltage fluctuation from -15 to + 10%.

Rated supply voltage 380 or 660V.

We select electrical equipment according to climatic conditions of UHL.

Electrical equipment can be continuously operated at ambient temperature exceeding the effective one.

The dust content of air is 10mg/m3, therefore, electrical equipment is used according to the degree of protection IP44.

Calculation and selection of mechanical gear kinematics elements

The elements of the kinematics of the mechanical transmissions of the conveyor include: belt, drum, rollers, reduction gear.

2.3. Calculation and selection of drum diameter

We select the diameter of the drums according to GOST 1062463 by the width of the belt 700800mm, the diameter of the drum 500mm.

The diameters of the drums are determined mainly by the purpose of the drum (driving, tensioning, deflecting, turning) and the conveyor

Analysis of possible variants of conveyor electric drive power channel

This electric drive power channel is designed for alternating current, voltage 380V, current frequency 50 Hz. Both adjustable and non-adjustable versions of the electric drive are possible.

An unregulated electric drive with an asynchronous motor with a short-circuited rotor, on such motors will not provide the required mechanical characteristics, since they will be the same, and we need one mechanical characteristic to be softer, therefore, this version of the electric drive power channel is not suitable for us.

A non-adjustable electric drive with an asynchronous motor with a phase rotor is possible. This version of the electric drive is not suitable. Since one engine will close the last stage briefly, and the other will remain part of the resistance, providing the necessary softness of the mechanical characteristic. This option is convenient at a constant constant load, but this is not real, since coal of different weights is transported over certain periods of time.

When the weight of the conveyed conveyor is reduced, the efficiency is greatly reduced and the energy consumption is greatly increased. Therefore, this option is not economical.

Structural diagram of electric drive

Initial data for IF selection:

1) Power, kW 55

2) Mains voltage, V 380.50Hz

3) Frequency control range, Hz 40-60

4) Presence of built-in PID regulator

5) High quality of sinusoidal output voltage with pulse-width modulation at least 4.5kHz

6) IGBT-based IF power modules

7) Control method volt-frequency quadratic (U/f2)

8) Remote (up to 5km) control room

9) Ambient temperature, 0С -0 + 40

10) IP-44 Security Standard

When selecting IF for our system as alternatives, three firms considered IF in more detail

SIMENS-GERMANY

YASKAWA-JAPAN

"UNIVERSAL" - RUSSIAN developer of MPEI, department of automated electric drive.

These last generation converters are based on the new IGBT power modules (Insulated Gate Bipolar Transistorbipolar Transistorbipolar Transistor with isolated gate), designed for currents up to several kiloampers, voltage up to several kilovolts and having a switching frequency of 30 kHz and higher. The structural power scheme of these IF is composed of a rectifier, a filter and an inverter. Due to the presence of an intermediate DC voltage circuit of this type, it is possible to change the frequency of the mobile voltage of the network, both downward and upward from its nominal (50 Hz) value. Inverter, as output stage of which is performed on the basis of IGBT modules, performs inverse conversion from DC to AC with necessary change of voltage and frequency using high-frequency pulse width modulation (PWM). In this case, IF output signal is a sequence of constant amplitude and variable duration voltage pulses, which on inductive load, which is the stator winding of the motor, generates sinusoidal-shaped currents.

The requirements for a frequency-controlled electric drive are determined by the range of required rotation speeds and the type of load. Depending on the nature of the load, the converters in question may provide different motor control modes, realising a particular relationship between the motor speed and the output voltage, for example, a mode with a linear relationship between voltage and frequency (U/f = const), a mode of quadratic dependence (U/f2 = const). The latter mode is most characteristic for regulating the electric drives of vane pumps and fans.

The mode with a linear relationship between voltage and frequency is implemented by the simplest frequency converters to provide a constant load moment and is used to control synchronous motors or asynchronous motors connected in parallel. At the same time, when the frequency decreases, starting from a certain value, the maximum moment of the engine begins to fall. To increase the moment at low frequencies in the IF, a function is provided to increase the initial value of the output voltage, which is used to compensate for the moment drop for loads with constant torque (conveyor) or to increase the initial moment for loads with high starting torque, such as, for example, an estroder, an industrial mixer.

The listed control modes are sufficient for most applications. At the same time, to improve the quality of the drive, the use of other, more modern control methods is required. These include the Flux Current ControlFCC method and the Sensorles Vector ControlSVC method.

Consider an adjustable electric drive. Take the speed control range D = 10. The speed control can be carried out by means of two frequency converters, one converter per engine, but the necessary softness of the characteristics will not be carried out .

In our case, an electric drive with one frequency converter and two asynchronous motors with a phase rotor connected in parallel is most convenient. This electric drive provides all technical and economic indicators.

6.1. Frequency converters of "UNIVERSAL" series.

IF "UNIVERSAL" are designed to control the speed of rotation of pumps, fans, compressors, drilling, ship and other mechanisms using asynchronous motors with a short-circuit rotor as drive.

Converters are issued in the power range from 0.55 < < A > > (0.55; 0.75; 1.1; 1.5; 2.2; 3.0kW) non-programmable, < < B > > (1.5; 2.2; 3.7; 5.5; 7.5; 11; 15 kW) -programmed by the manufacturer, < 75; 220 > > (15; smart; 160; 45; The converters of this power subband discussed in the present information material have uniform principles for constructing the power and control parts.

Description of electrical circuit operation

9.1. Functions performed by the schema

Electric control circuit provides operation of conveyor in automated mode with performance of the following functions, namely:

automatic start of the conveyor from the control panel;

providing a warning signal on the conveyor line before starting it;

stopping the conveyor, both from the control panel and from the control unit;

disconnection of the conveyor at actuation of various kinds of protections;

stopping the conveyor when there is no supply voltage on the alarm device, when the belt speed exceeds the drive drum on the conveyor, i.e. disconnecting the contact of the relay device, when the contact of the fire extinguishing unit is opened, there is no pressure in the fire pipeline;

monitoring of conveyor start-up time;

control of reduction of belt speed from nominal speed and application of brakes at belt speed less than or equal to 0.5 m/s;

emergency disconnection of the tension winch starter and conveyor drive if the belt tension exceeds the permissible limits set on the pressure gauge or if the tension carriage is in the extreme position and acts on the switch; light and sound signalling when the conveyor is disconnected due to actuation of protections.

Power supply

10.1. Selection of power supply system

In accordance with the instructions of the Instructions for the design of electric installations of coal mines, it is recommended to design without permanent duty personnel using automation and alarm devices for emergency disconnections.

Selection of the number and design of 6· 220kV power supply lines for new and reconstructed mines is made depending on the methane availability, water availability and climatic conditions in the area where the mine is located.

The design of power supply should be carried out based on the prospects for the development of the enterprise.

The internal power supply networks of coal-fired enterprises include distribution networks with a voltage of 110, 35.6, 10.04/0.23kV within the boundaries: assembly buses 110.35, 6, 10.04/0.23kV of the main lowering substation (GPP) - electric receiver clamps. These networks serve as a continuation of the power system and provide power supply to the workshops of the enterprise, technological units and individual electric receivers. The configuration of the internal power supply networks of the enterprise depends on:

numbers, power, voltage, operation mode of the main machines and mechanisms;

continuity and degree of redundancy of receivers and enterprise as a whole;

the master plan of the enterprise;

power supply characteristics (voltage, power).

These factors depend on: the production capacity of the enterprise, the number and location of the shafts, the size of the mine field, the depth and water availability of the mine, the size and shape of the area of ​ ​ open developments, capacity, etc.

Internal power supply networks of enterprises are a set of main lowering or distribution substations and distribution networks.

In the practice of operating coal enterprises, two main power distribution schemes have become widespread: radial and main. The enterprise as a whole uses a combined internal power supply scheme, which is a combination of radial and main circuits.

In the radial distribution scheme, the supply lines from the power supply (MPP, RP), to each consumer, distribution point or transformer substation are made without branches on the way to supply other consumers.

With the main power distribution scheme, several consumers are supplied via one or more lines brought to the distribution points of these consumers.

Power supply of electric receivers with voltage up to 1000 V in underground workings of coal mines is carried out from underground section mobile substations. Recently, some distribution has been received in the underground workings of the electric receiver at a nominal voltage of 1140V. These consumers are also fed by PLCP.

The project includes two types of precinct substations:

stationary - for power supply of electric receivers of stationary mechanisms,

mobile - for power supply of electric receivers of mobile machines and mechanisms.

I install stationary substations in chambers with a lattice door, without fire doors. In such a substation, the plant accepts as dry transformers in explosion-proof design, current and mobile transformer substations (PLCP) in the amount of one to three.

For the mines of the coal basin near Moscow, where the usual mine field preparation system is used - panel with long poles, the power supply systems are noticeably different from the usual ones. The peculiarities of power supply systems in the coal basin near Moscow are determined by the following main conditions:

Mines are not hazardous to gas or dust, although they are in gas mode.

Depth of formation is 5070m.

Power supply of power consumers in the area is carried out with voltage of 380V or 660V through wells from transformer kiosks installed on the surface.

Transport along the prefabricated panel hatch - electric locomotive.

In case of shallow formation occurrence (up to 400 m) in some cases, it is advisable and economical to supply underground electric receivers from the surface through power wells.

At this method of power supply of electric receivers, electric power is transmitted from PE of the mine to power wells via air and cable power lines 610kV, as well as via air power lines 35110kV, from the head of power wells to PE with voltage of 0.666kV via cable power lines of the corresponding voltage.

Power supply of sections through the well allows:

a) reduce the cost of 6kV networks by replacing expensive underground cable lines with cheaper air power lines;

b) reduce the cost of electrical equipment by a voltage of 6kV due to the use of general industrial electrical equipment instead of explosion-safe design;

c) reduce the construction of underground structures for RPP6 and PLCP;

d) increase the safety of maintenance of the power supply system and application of electricity in underground workings by reducing the length of networks, which will provide protection against single-phase earth faults.

Method of feeding section through well with low voltage of 660V is applied. The site receives electric power from the general station via power line -10kV. TM630kV· A transformer is installed on the power well. Electric power is supplied from the transformer via two 3x70 SS cables to the power well chamber. The calculated area is one lava equipped with a complex. The site operates in 3 shifts for coal mining and one shift for repair.

Disadvantages of the well feed scheme include:

the need for frequent movement of wells under conditions of voltage loss,

the need to drill wells and fix them with casing pipes with a diameter of 125, 150 mm, which are not usually extracted and reused.

10.3. Protection of cables and electrical equipment installed in underground workings

In accordance with the PB in underground networks with a voltage above 1140V, lines, transformers and electric motors must be protected from DC currents.

Overload current protection and zero protection shall also be provided for motors. In all cases of disconnection of the network with protections, it is allowed to use a single-action automatic re-on (ATS) and devices for automatic switching on of equipment with interlocks against voltage supply to the lines and electrical installation in case of damage to their insulation relative to the ground and short circuit.

The use of junction boxes without installation on branches to electric motors of protection devices is allowed only for multi-engine drives, provided that the cable of each branch is protected from DC currents. group protection apparatus.

Cables laid in the lava shall be protected against mechanical damage by devices included in the complex or other means of mechanical protection of cables.

The nearest part of the flexible cable supplying the mobile machines to the machine can be applied over the soil for not more than 30 m. During the operation of combine harvesters and pipe machines on formations with a capacity of up to 1.5 m, it is allowed to lay a flexible cable on the soil of the treatment plant .

Flexible energized cables shall be stretched and suspended to avoid overheating. Current loads on cables, which under operating conditions should be in bays or on drums, should be reduced by 30% of the nominal.

The selection of relay protection devices, as well as the calculation and verification of the actuation parameters of these devices should be carried out in accordance with the Instructions for the selection and inspection of electrical devices voltage 346kV.

Automated Conveyor Accessory

When automating the conveyor plant, in addition to start-up and control equipment, automatic monitoring devices for the condition of individual conveyor units are used. These include devices for monitoring the presence of material on the tape, places of overload, descent and slip of the tape, tension of the traction element and its break.

11.1. Tape Release Control

The improper loading of the belt conveyor and the uneven drawing of the belt, the poor installation of the conveyor stand, the sticking of material to the drums and rollers - all lead to the belt deviating to the side and leaving the roller supports. Various centering roller supports are used to eliminate tape descent. However, the practice of using them has shown that the existing designs of such roller supports do not provide reliable alignment of the tape.

AKL1 device is used to control belt release and conveyor disconnection in case of belt deflection. It consists of two limit switches equipped with a lever. On the lever there is a control roller, which in normal condition rolls over the non-working side of the belt. If there is no tape under the roller, the lever turns under the action of the load and switches over the contacts of the switch. In this case, the coil of the RCL relay is de-energized, which turns off the conveyor starter. The device controls the tape release in both directions

11.2. Tape slip and break control

To prevent long-term slip of the tape, a slip monitor is used.

This device also responds to tape rupture, violation of the integrity of the roller supports and the operation of the engines.

In case of normal movement of the belt, the period of complete rotation of the lever fixed on the axis of the driven drum of the conveyor will be constant in time. The slip time relay of the VRP is adjusted so that the release time of its closing contact is slightly longer than the period of full rotation of the lever. When the lever rotation time increases, which can be caused only by tape slip, the RVP relay opens its contact, since the closing contact of the final switch of the RVP slip will open longer than the time of the received installation of the RVP relay. As a result, the RTD contact opening loses power to the conveyor starter coil .

The belt slip control device disables the conveyor when the belt is broken. However, on the inclined conveyor, the break of the belt leads to its sliding down and a severe accident. Therefore, belt catchers are necessarily installed on modern inclined conveyors - belt retaining devices when it breaks.

11.3. Registration of transported goods

Cargoes are part of the overall management of the transport line and are always closely linked to planning and operational management. With the complete automation of accounting, all operations for the collection, processing and issuance of accounting information are carried out automatically. To automate accounting in this case, we use the weight method of accounting.

This method involves weighing without leaving the transportation area. The weight measuring device in this case is an integral part of the conveyor, which does not lead to a decrease in the productivity of the conveyor unit. Commercially available continuous belt weighers are widely used as high-measurement devices built into conveyor lines. We use structurally unified continuous scales designed for automatic weighing. Scales are made in form of transport mechanism.

The force from the weight of the material on the conveyor belt suspended on the four suspension of the weight mechanism to the frame is transmitted through a system of levers to a balancing mechanism consisting of a metrological spring, a damper and two electric differential-transformer measuring converters, such as PD5.

Each mass of material corresponds to a certain position of the metrological spring and, accordingly, of the converter plungers. The measurement scheme is based on instruments of the frequency-ferrynamic model. The signal of one converter of measurement is given on an entrance of the measuring VFS24SRR device which is carrying out indications and record of instant performance. Device has two output converters of ferrodynamic and frequency signal of the latter is supplied to input of frequency adder of C4 type showing total mass of material passed through scales.