Power supply of mechanical workshop

Introduction

In order to create reliable and economical power supply systems of various enterprises and industries, the design should be guided by modern methods of electrical calculations, regulatory guidelines and guidelines, such as: guidelines for calculating loads, guidelines for calculating short-circuit currents and selecting electrical equipment, rules for the arrangement of electrical installations, etc.

Electrification ensures the fulfillment of the task of wide complete mechanization and automation of production processes, which allows increasing the growth rate of public labor productivity and improving the quality of products and facilitating working conditions. Based on the use of electricity, technical re-equipment of industry, the introduction of new technological processes and concrete changes in the organization and management of production are being carried out.

The main calculations necessary to perform the task: calculations of electrical loads taking into account reactive power compensation and calculation of short-circuit currents. KTP power transformers, main conductors and switching equipment as well as lighting equipment on the construction site are subject to selection.

Characteristics of the design object

1.1 Characteristics of the production area and mechanization facilities at the design site

The mechanical workshop can perform various repair, production works, as well as perform scheduled and unscheduled technical services and inspections of vehicles and units for this type of work at the enterprise installed special equipment that allows performing complex repair work. The mechanical workshop has lathes, with the help of which work is carried out on the manufacture of some parts and units of transport, thread cutting and other works. Round grinding, drilling and milling machines are also installed, which play an important role in the repair. In the workshop there are fan plants, with the help of which air is ventilated around the working areas of the perfect version of the construction of this object.

Operations to move loads inside the shop are performed using a crane beam.

The workshop provides a room for a transformer substation, a machining area, a machine park, ventilation and welding.

The workshop building is made of brick, the floor inside the room is concrete.

Shop dimensions: AhVxN = 45x30x7 m.

The soil around the building is loam.

The workshop provides both natural and artificial lighting.

Automation of equipment

Electrification ensures the fulfillment of the task of wide complete mechanization and automation of production processes, which allows increasing the growth rate of public labor productivity, improving the quality of products and facilitating working conditions. Based on the use of electricity, technical re-equipment of industry, the introduction of new technological processes and the implementation of fundamental transformations in the organization and management of production are carried out.

Of paramount importance for automation of production are multi-motor electric drive and electric controls. The development of electric drive follows the path of simplifying mechanical transmissions and approaching electric motors to the working organs of machines and mechanisms, as well as the increasing use of electric control of drive speeds.

In this diploma project, the pump plant system was automated using a frequency converter. This will further save on the operation of the pump unit by reducing the cost of electricity.

3.1 Literature Overview of Advanced Technologies

Main trends in the development of built-in engine control systems and requirements for microcontrollers

Modern electric drive represents structural unity of electromechanical energy converter (motor), power converter and control device. It converts electrical energy to mechanical energy in accordance with the operating algorithm of the process unit. The field of application of electric drive in industry, transport and everyday life is constantly expanding. Currently, more than 60% of all electricity generated in the world is consumed by electric engines. Consequently, the efficiency of energy-saving technologies is largely determined by the efficiency of the electric drive. The development of high-performance, compact and economical drive systems is a priority for the development of modern technology.

The last decade of the outgoing century was marked by significant successes of power electronics, the industrial production of isolated-gate bipolar transistors (IGBT), power modules based on them (racks and entire inverters), as well as power intelligent modules (IPM) with built-in key protection and interfaces for direct connection to microprocessor control systems.

The increasing degree of integration in microprocessor technology and the transition from microprocessors to microcontrollers with an integrated set of specialized peripherals made the trend of mass replacement of analog drive control systems with direct digital control systems irreversible.

Direct digital control means not only direct control from the microcontroller by each switch of the power converter (inverter and controlled rectifier, if any), but also providing the ability to directly input various feedback signals to the microcontroller (regardless of the type of signal: discrete, analog or pulse) with subsequent software and hardware processing inside the microcontroller. Thus, the direct digital control system is focused on eliminating a significant number of additional interface cards and creating single-board drive control controllers. Within the limit, the integrated control system is designed as a single-chip and, together with the power converter and the actuator motor, is structurally integrated into an integral mechatronic motion module.

3.4 Development of electrical schematic diagram

Power is supplied from a 380 V three-phase mains. Protection is provided by the QF1 circuit breaker. Power is supplied to the control circuit by means of KM1 starter. The coil of this starter is fed through the step-down transformer TV1. The pump alarm system also takes power from it. Press button SB1 to put the pump unit into operation. Then the starter coil KM1 will be powered and close its power contacts, thereby supplying power to the frequency converter system of the pump unit. Then the pump starts operation according to the specified program. The frequency converter system consists of two control units and an engine unit - a liquid level sensor. Use switch S1 to select the pump program. Then, the control unit generates signals and supplies them to the input of the frequency converter through contacts 728, 727. The frequency converter generates an input signal to the motor S. The liquid level sensor S provides a reverse signal to the converter. The pump electric drive control system is thus feedback.

Feasibility study

A well-designed estimate for electrical installation is an opportunity to estimate the amount of future financial costs and, if necessary, reduce them.

The purpose of the thesis is to determine the estimated cost for the installation of the pump unit control board, which in turn serves as the basis for determining the amount of capital investments and financing the project.

The basis for determining the estimated cost of the project is the initial data of the customer, the project documentation, the bill of quantities and the specifications for the purchase of equipment.

The steps in the preparation of the estimates are:

1 Selection of the calculation method;

2 Determination of direct costs for the specified scope of work, indexing of base prices ;

3 Determination of overhead costs calculation of estimated cost of works;

Determination of estimated profit, calculation of estimated cost of works.

4.1 Economic and legal situation of the organization

OJSC Izhevsk Plastics Plant is an advanced enterprise for the processing of polymer raw materials and the production of crosslinked foamed polyolefins. It was built in 1972 as a satellite plant of the automobile production of the Izhmash association. Today, the Izhevsk Plastics Plant is the largest company in Russia and the CIS for the processing of polyethylene foam under the ISOLON trademark. Modern equipment, the latest technologies, the level of quality that meets the highest standards, a careful attitude to the environment - all this allows factory workers to be proud of the results of their work and confidently look to the future. Due to the competent organization of production, the constant search for new equipment capabilities, the use of original technological solutions, the plant managed to take a worthy place in the Russian and foreign markets and achieve a stable economic situation. A worthy participant in the international market, certified according to the international standard ISO 9001:2008. The plant's products are delivered to 16 countries near and far abroad.

Characteristics of the study object

The pump unit is called a pump unit, the component equipment of which is installed according to a certain scheme that ensures the operation of the pump. The figure shows the diagram of the pumping unit for liquid transfer. The pump driven by the electric motor sucks the liquid from the service tank and pumps the liquid to the receiving tank via the suction line and the pressure line.

Each pump unit shall have a log (or passport) containing the following sections:

logging rules;

performance of regulations and works on the plant (equipment) during operation;

metering of plant and equipment operating time;

accounting of technical inspections of the plant and equipment;

recording of plant and equipment malfunction;

assessment of the state of the plant and equipment ;

recording of changes in the composition of the pump unit and equipment .

The above mentioned types of works are performed on the basis of documents (passports) of pump unit elements.

4.3 Installation Production Technology

As intended, electrical panels and control panels can be:

operational, from which the process is controlled and monitored;

non-operational, intended only for installation of devices, instruments and devices not used directly for process control and monitoring;

combined, which can perform both operational and non-operational functions.

According to design design, electric panels can be:

external or internal installation;

floor and hinged;

metal and plastic;

cabinet one-, two- and multi-section;

front, rear and double-sided doors.

For modern automation systems, taking into account the use of microcontrollers, all control equipment can be placed in hinged one-sided small-sized cabinets, and non-operational equipment in plastic modular panels.

For installation of boards and control panels, it is necessary to have a wiring diagram, a sketch drawing of a general view with a list of all elements, including installation accessories.

The following shall be taken into account when arranging automation equipment on boards and panels:

purpose and number of devices and devices;

ease of installation and operation;

aesthetic aspects of appearance;

service security.

Almost all modern devices and devices are designed to be installed on a DINrack, which can be attached to the rear wall of the cabinet, a special panel or behind the racks on the side walls of the cabinet. This attachment is reliable enough to allow quick and easy installation or removal of the machine.

The configuration and dimensions of the DINracks are given in IEC 6094772.

Usually, in the cabinet on the DINRacks, connection terminals are also installed, combined in size depending on the section of the connected wires. They are designed both for connecting external wires and for connecting devices located on different panels of the cabinet (for example, on the door).

The range of terminal joints produced is very extensive both in design (screw, spring, for quick installation, single and multi-tier, etc.) and in electrical parameters (clamping section from 0.14 to 240 mm2, current up to 400 A and voltage up to 1000 V).

If separate control panels are not provided in the design, the following shall be arranged on the front panels or front doors of the control cabinets:

measuring and regulating instruments;

light signal equipment;

operating equipment (buttons, switches, etc.);

mnemonic diagrams.

The listed devices are assembled by functional groups usually in the order of the process.

For floor control cabinets, the recommended height of the control equipment installation is (in mm from the floor to the lower edge of the device):

showing devices and signal equipment: 950-1800;

self-recording and recording devices: 110-1700;

operational control equipment: 800-1600;

mnemonic diagrams: 10001900.

Preference is given to the lower bound. The same values shall be adhered to when installing the mounted control cabinets directly on site.

The devices and devices are connected to each other in accordance with the connection diagram. According to SNiP 3.05.0785, connection of single-wire copper conductors and cables of 0.5 and 0.75 mm2 section and multiple-wire copper conductors of 0.35, 0.5 and 0.75 mm2 section to instruments and devices, clamp assemblies should, as a rule, be performed by soldering, if the design of their leads allows this. If copper strands of the specified sections are attached to devices having leads for connection under a screw or bolt, then the strands of these wires and cables must be terminated with a tip.

Single-wire copper wires of wires and cables with a section of 1.0; 1,5; 2,5; 4.0 mm2 can be connected directly under the screw or bolt, and multicore wires of the same or large sections can be connected using tips.

Each end of the wire or cable core at the point of connection to the set or device shall be numbered with the electrical circuit number according to the wiring diagram.

The easiest method of marking is to apply a number with a marker (special marker) on a section of PVC tube, which is put on the end of the wire before it is connected to the apparatus.

A more progressive method is to use a holder that snaps onto the connected wire and into which a nameplate with an electric circuit designation is inserted.

Previously, connecting wires were grouped into bundles using harsh threads and other tape insulation materials. Such a technology was very laborious, unestetic and caused inconvenience during adjustment and repair (in order to replace the wire, it was necessary to cut the entire harness).

The above mentioned disadvantages are completely eliminated when using perforated boxes installed along the perimeter of the mounting plane and between rows of devices. In this case, the installation is carried out without laying wires, and after its completion, the boxes are closed with covers, which makes the view inside the cabinet more aesthetic. A spiral tube is used to combine the wires of the inter-panel flexible connection (for example, between the inner panel of the cabinet and the equipment on the door).

Depending on the place of installation and the corresponding degree of protection (IP), the cabinets and panels of the automatics should be equipped with introductory devices of the appropriate types.

So, for ordinary rooms, it is sufficient to install a rubber seal on the outlet side of the cabinet, in which a hole for the supply pipe with minus tolerance is cut out. For more difficult operating conditions, special cable tips are used. The entire cabinet design in terms of IP protection shall comply with the same conditions.

Panels and panels are installed on the site after completion of all construction and main finishing works, construction of cable channels, openings for the introduction of cables and pipes, foundations and embedded steel structures.

The conditions for installation of boards and consoles are determined by the projects, however, there are a number of general requirements that are provided in SNiP 3.05.07-85:

full-sized cabinet and panel boards are installed only on supporting steel frames or on a concrete (brick) base;

small-sized cabinet boards and modular boards are usually mounted on columns, walls, openings and other building structures (mounted) or on floor tinctures; fastening is carried out by means of bolts, holes for which are located on the rear wall of the cabinet;

The spatial position of the panels and cabinets shall be strictly vertical and horizontal;

if there are vibrations in the place of installation of boards and panels, special damping devices shall be used;

floors in the room where panels and panels are located must not be electrically conductive;

electrical wiring to shields and consoles is usually introduced from below through rubber seals;

metal boards and panels are subject to mandatory grounding.