Electrical equipment and control diagram of lathe 16D20

Contents

Contents

Introduction

1 Purpose and technical characteristics of the machine

2 Technical justification of selection of electric drives of main and auxiliary motion

3 Power calculation and selection of the main motion motor type

4 Power calculation and selection of auxiliary motor type

5Recalculation and construction of mechanical characteristic of main motion motors on PC

6 Development of schematic electrical control diagram

7 Development of the appearance of the machine with the arrangement of electrical equipment

8 Selection of start-up, protection and control devices 22 9 Occupational safety

Conclusion

Literature

TNAP List

Appendix A - the Schematic electric circuit of management

Appendix B is Appearance of the machine with location of electric equipment

Introduction

Electricity is a strategic industry whose state is reflected in the level of development of the state as a whole. Currently, the electricity industry is the most stable working complex of the Belarusian economy [1]. Enterprises of the industry provided efficient, reliable and sustainable energy supply to consumers of the republic without accidents and significant environmental damage.

The main priority of our state's energy policy is to increase the efficiency of energy use as a means to reduce the costs of society for energy supply, ensure the sustainable development of the country, increase the competitiveness of productive forces and protect the environment.

Over the past few years, the Concept of the National Strategy for Sustainable Development and the Basic Directions of the Energy Policy of the Republic of Belarus have been developed and approved by the highest authorities and the Government. The development and refinement of these fundamental documents, taking into account changes in the internal and external factors of the development of the Republic of Belarus, in 2003 developed the country's fuel and energy balance for the period until 2020, in which issues of further development of the electric power industry are also given an important place.

Electricity consumption in the republic in 2020 will grow to 41 billion kVt∙ch (23% higher than in 2000). Imports of electricity will not exceed 4 billion kVt∙ch and, depending on market conditions, may be stopped, since the installed capacity of its own generating sources will ensure the necessary volume of electricity production.

Electricity consumption by the industry is expected to decrease by 13%, and the utility sector will become the main consumer of electricity.

However, its share should be reduced to 60% of the total consumption of boiler fuel due to increased consumption of fuel oil, coal, firewood and hydropower resources.

Machine 16D20 found its use at the Minsk Wheeled Tractor Plant OJSC in the frame and press workshop, where it performs a wide range of turning work in finishing and semi-cleaning modes. The machine provides the cutting of metric, inch, modular threads, as well as the stretching and turning of blanks .

Technical justification of selection of electric drives of main and auxiliary movements

2.1.Technical justification for selection of electric drive of main motion

The speed control range of the lathe spindle reaches (12.51500): 1. At the same time, it is desirable to have its change as smoothly as possible in order to ensure in all cases the most profitable cutting speed. [2]

For lathe machines in which the main motion is rotational, power constancy is usually required in most of the speed variation range and only in the low velocity region is the torque constancy equal to the highest allowable strength of the main motion mechanism. Small speeds of rotation are intended for specific types of processing: thread cutting by marks, turning of welds, etc.

In the main drives of lathe and carousel machines of wide purpose of small and medium sizes, the main types of drive is a drive from an asynchronous short-circuited motor. The asynchronous motor is structurally well combined with the speed box of the machine, reliable in operation and does not require special care. The speed of the spindle of the machine in such a drive is controlled by switching the gears of the gearbox.

In small lathes, starting, stopping, changing the direction of rotation of the spindle is often carried out using friction clutches. The motor remains connected to the mains and rotates in one direction.

For the main drive of some machines, multi-speed asynchronous motors are used. The use of such a drive is advantageous if it results in simplification of the speed box or when it is required to switch the speed of the spindle on the go.

As a rule, heavy lathes and carousel machines have electromechanical stepwise-smooth control of the speed of the main drive using a DC motor. A relatively simple speed box of such machines produces two to three angular speed stages, and in the interval between the two stages is carried out in the range (3-5): 1 smooth control of the angular speed of the engine by changing its magnetic flux. This, in particular, makes it possible to maintain constant cutting speed during turning of end and cone surfaces.

If there is a constant load moment in the specified range of spindle speed of the section, it is advisable to apply two-zone electric control of engine angular speed. This makes it possible to simplify the speed box and increase the use of the engine in the zone of constancy of the load moment. A feature of the main drive of the carousel machines is the high moment of friction forces at the beginning of the start, the insignificant moment of inertia of the plan washer from the part, which exceeds at high mechanical speeds 8-9 times the moment of inertia of the motor rotor. The use of a DC electric drive in this case provides a smooth start with constant acceleration.

In the workshops of machine-building plants, there is usually no direct current network, so separate converter devices are installed to power the engines of heavy machines: electric machine (G-D system) or static (TPD system).

Stepless electric speed control (two-zone) is used in the automation of machines with a complex cycle of work, which allows you to easily re-set them to any cutting speeds (for example, some turning-turret machines). Stepless electric control of the speed of the main drive is also used for some precision lathes. But in all these cases, the speed control range with constant load power does not exceed (4:5): 1, in the rest of the range, the control is carried out with constant load moment.

For the main drive, the 16D20 lathe-screw machine accepts a drive from an asynchronous motor with a short-circuited rotor in combination with a speed gearbox.

2.2.Technical justification for selection of electric drives of auxiliary movements

The drive for the supply of small and medium lathes is most often carried out from the main engine, which provides the possibility of thread cutting. Multi-stage feed boxes are used to control the feed speed. Switching of stages is performed manually or using electromagnetic friction couplings (remotely) [2].

Some modern heavy lathes and carousels use a separate widely adjustable DC electric drive to drive the feed. The angular speed of the engine varies in the range up to (100200): 1 or more; drive is performed by EMDS, PMU-D or TPD system.

Separate short-circuited asynchronous motors are used for auxiliary lathe drives (accelerated movement of caliper carriage, article clamp, coolant pump, hydraulic seal).

For actuators of auxiliary movements, the lathe-screw-cutting machine of the model 16D20 accepts:

- Drive fast displacement asynchronous motor with short-circuited rotor;

-cooling pump drive asynchronous motor with short-circuited rotor.

Development of schematic electrical control diagram

Three-phase short-circuit asynchronous motors are installed on the machine and the following voltage values ​ ​ are used:

Power circuit - 380V, 50 Hz;

AC control circuit - 110 V, 50 Hz;

Local lighting circuit - 24 V.

Switching on the input circuit breaker is possible only if there is a voltage in the network, and turning on the main drive motor only when the electric cabinet door is closed. Turn on the QF1 circuit breaker. Press SB6 button, get power to KM1 contactor, close its contacts KM1: 1... 3 in power supply circuit of M1 main motion motor, close KM1: 5 contact sets the contactor for self-energizing, opens KM1: 4 contact to block reverse actuation. To perform reverse actuation of the engine, press the SB5 button, energize the KM2 contactor, close its contacts KM2: 1... 3 in the power supply circuit of the M1 engine, reverse occurs. To start the cooling engine, press the SB3 button, energize the KM3 contactor, close its contacts KM3: 1... 3 in the supply circuit of the cooling engine, close its contact KM3: 4, set the contactor to self-energize, the engine is started. Auxiliary motion motor is actuated by limit switch. The KM4 contactor receives power, closes its contacts KM4: 1... 3, connecting the engine to the network.

Development of the appearance of the machine with the arrangement of electrical equipment

The main electrical equipment is placed in production plants differently depending on the type and size of industrial mechanisms. In transport devices (bridge cranes, telphers, etc.), on small and medium metal cutting machines, presses, hammers and other machines, electrical equipment is installed on the mechanism itself [2].

In most industrial installations (heavy metal cutting machines, powerful presses, pumps, compressors, etc.), electrical equipment (EO) is located on and off the mechanism itself. On the mechanism, an EO is installed, which is structurally connected with the working elements of the machines. Outside the mechanism there is an EO with large dimensions and mass, as well as cabinets with control equipment.

In metal cutting machines, hammers and presses, motors are typically mounted directly on machine and machine housings or embedded inwardly. At the same time, it is necessary that cooling air access to the engine is provided, but oil or coolant penetration into the engine is excluded. If the DG system is used, then the synchronous motor, generator and exciter are installed usually outside the mechanism coaxially on the common plate in a row, forming an electric machine unit.

If there is a tachogenerator in the control circuit of the electric drive, its shaft is rigidly connected to the motor shaft using a key clutch or an elastic connection is used using a rubber-fabric clutch. Engines of the new series have a built-in tachogenerator .

Typically, electrical control equipment (relay or contactless) is placed in electric cabinets that are installed near machines and machines, and with small sizes of electric cabinets - directly on mechanisms. It is inappropriate to install cabinets far from production machines, as the cost of installation increases, voltage drop and losses in long wires increase.

A small cabinet can be attached to the wall of the machine body (head) or is made in the form of a panel installed on the machine and a closed door. If the device is possible in the wall of the niche housing or window, it is advisable to use a cabinet of built-in or insulated design. In the built-in design, the panel is mounted on the inner vertical wall of the niche by the door. In the recessed design, the panel is fixed on the inside of the door covering the window in the wall of the housing.

For complex or bulky electrical equipment, as well as in cases when, due to the vibrations of the machine or machine, cabinets attached, recessed or built-in, versions cannot be used, an external electric cabinet is used. In this case, it is desirable to use the entire height of the cabinet, which should not exceed. The outer cabinet frame is usually made of corners and sheathed in sheet steel.

According to the method of installation and access to equipment, external electric cabinets are made one-sided and two-sided. In single-sided cabinets, the front connection of wires to sets, which can be accessed through the opening of the cabinet door, is used. In double-sided cabinets, the equipment is placed on two sides of the vertical panel with a front or rear connection of wires. If the equipment does not fit in one cabinet, two or three cabinets shall be used. Cabinets of all versions are equipped with a lock with a removable key.

Conclusion

During the course project, the electrical equipment and control diagram of the lathe 16D20, I studied the purpose and technical characteristics of this machine.

The power of the main and auxiliary engines of the 16D20 machine was calculated. The mechanical characteristic of the main engine was also built using PC. During the construction of the mechanical characteristic, the moments and slips at which the engine worked stably were determined, as well as the values ​ ​ of critical moments and slips, the excess of which would negatively affect the operation of the machine.

A diagram of the appearance of the machine with the location of electrical equipment was developed, in which the location and designation of the outputs of electrical equipment was reflected. A schematic electrical diagram of the machine was also developed.

Starting, protection and control devices were selected in accordance with the reference literature and the obtained values ​ ​ during calculations.