Industrial enterprise
Proper organization the workplace ensures rational movements of the worker and reduces to a minimum the time spent on finding and using tools and materials.
When designing a workplace It is necessary, first of all, to strive to make a person’s work easier, create maximum comfort for him, and make the workplace safe and comfortable.
In this case, the size and shape of the human body, its mass, the strength and direction of movement of the arms and legs, and the characteristics of vision and hearing must be taken into account.
In this case, must be observed optimal sizes working area, for placing tools, materials, devices, devices and for performing work operations.
Let's describe an approximate diagram of the organization of electrician's workplaces (Figure 2)
Mobile table 1 is used for disassembling, washing and assembling various electrical equipment. It also serves as a vehicle for carrying cargo. The tabletop is lined with laminated paper with a steel corner edging. At the bottom of the table there is a metal shelf made of steel sheet 1.5 mm thick, designed for storing technological equipment and auxiliary materials. The table is mounted on wheels (with a rim made of oil-resistant rubber) with rolling bearings. This provides good maneuverability and does not require much effort to move it.
Workbench 2 consists of two cabinets each having five drawers with trays, in which plumbing and measuring tools, instruments, spare parts, electrical equipment, fasteners and auxiliary materials are placed; drawers on frames with central locking; the top drawer of the cabinet and the middle drawer for documentation, closed with a top lock; countertops; desktop switchboard with an alternating voltage of 380 V supplied to it, and a removed voltage of 6, 12, 24, 36, 127, 220 V
and two alarm panels for calling an electrician from 30 workstations (30 points); a desktop cabinet with spare parts and a telephone for communication with plant subscribers.
Rack cabinet 3 is designed for storing large devices and spare tools used in the repair of electrical equipment. The upper compartments store various materials needed for repairs. Frame cabinet-rack painted with gray enamel.
The electrician on duty uses a portable bag to carry tools and measuring equipment, fixtures, and small parts for repairing electrical equipment in workshop areas.
The design of the chair-stool 4 allows for the most comfortable working position: the seat can be raised or lowered easily and quickly.
The workplace must be technical and accounting documentation, job descriptions, as well as documentation on safety and labor organization.
IN technical documentation includes electrical diagrams of the most complex machines, lifting and transport equipment, a circuit diagram of the power supply of a workshop (area) with electricity, an electrical diagram of distribution boards, etc.
Accounting documentation reflects equipment downtime and electrician work. One type of such documentation is an operational (operational) log. As a mandatory document, the workplace must contain labor safety instructions for shop electricians servicing electrical installations with voltages up to and above 1000 V.
To documentation on labor organization include a calendar schedule of scheduled inspections, a shift-hour schedule and a work organization map for the electrician on duty. Workplace must be designed in accordance with the requirements of technical aesthetics.
Work clothes electricians should be comfortable, not restrict movement during work and consist of a jacket, trousers and beret (beret bright color- red, orange or brown). Material - suit fabric with nylon fiber, plain dyed, blue. The top pocket of the jacket should have the emblem of the Chief Power Engineer service.
Electrician long time is on his feet, his work is associated with increased attentional stress (during a shift, an electrician on average performs up to 740 different work actions), so rest time should be at least 5% of the time worked.
Study theoretical material and answer questions
Exercise 1
Study the theoretical material and answer the questions:
1. Workplace (definition)
2. What factors need to be considered when designing a workplace?
3. When are labor movements rational?
4. What are the requirements for the layout of an electrician’s workplace?
5. Formulate in a table information about the equipment used at the workplace of an electrician on duty at an industrial enterprise
Table 3.1 – Equipment of an electrician’s workplace at an enterprise
6. Describe the documentary equipment of an electrician’s workplace at an industrial enterprise.
Table 3.2 – Documentary equipment of the electrician’s workplace
| Documentation | Content |
7. What are the requirements for the clothing of an electrician at an industrial enterprise?
8. How long should electricians rest at the enterprise? Justify your answer.
Task 2
Consider Figure 1. You should sketch and mark the work zones in the horizontal plane: 1, 2, A, B, C. Describe the purpose of these zones.
Task 3
Suggest measures to improve the organization of work at the workplace of an electrician on duty based on the experience of undergoing practical training at the workplace of an electrician at an industrial enterprise. Formulate the proposals in the following table:
Table 3.3 – Organizational and technical measures to optimize the organization of an electrician’s workplace at an industrial enterprise
CONTROL QUESTIONS
1. Define the concept of “workplace”
2. Requirements for the layout of an electrician’s workplace
3. In what cases are labor movements rational?
4. List the material and technical equipment of the electrician’s workplace
5. What documentation does an electrician use during his work?
6. What are the requirements for electricians’ work clothes?
LITERATURE:
1. Alekseeva M.M. Planning the company's activities: Educational and methodological manual. - M.: Finance and Statistics, 2011.
2. Knyshova E. N. Management: textbook. – M.: Publishing House “FORUM”: INFRA-M, 2010. – 304 p.
Practical work No. 4
Drawing up estimates for planned repairs and technical work
Equipment maintenance
Goal of the work learn how to prepare estimates for planned repairs and maintenance work maintenance equipment
To do the job you need to know:
– essence and classification of enterprise costs;
–economic elements of enterprise costs;
– the composition of costs included in the estimate of planned repairs and maintenance of equipment;
– methodology for preparing cost estimates.
To perform the job you must be able to:
– find and use the necessary economic information;
– draw up an estimate of planned costs for repairs and maintenance of equipment.
Completing this practical work contributes to the formation of professional competence PC 3.1. Participate in planning the work of production department personnel.
RUNNING TIME: 90 minutes
Cost estimate - this is a complete summary of the costs of repairs and overhaul maintenance of electrical equipment.
Costs for technical maintenance and repair of equipment when planning are grouped according to the following expense items :
1. workers' wages;
2. insurance contributions to extra-budgetary funds;
3. materials, semi-finished products and purchased components and finished products. The cost of basic materials for the repair of a conditional repair unit is calculated for each type of material separately;
4. expenses for production maintenance and enterprise management
Expenses for production maintenance and enterprise management (overhead costs) are the costs of maintaining and managing production and the enterprise as a whole. These include:
Ø shop expenses;
Ø factory overhead expenses.
Part shop expenses includes the costs of management, maintenance and maintenance of workshops: wages with accruals for the workshop management apparatus; wages with accruals for shop personnel; depreciation and maintenance of buildings, structures, equipment; costs of testing, experiments, research, rationalization; labor protection costs and other expenses
Factory overhead , allocated to cover the costs of managing and servicing the general economic needs of the enterprise, consist of: wages with accruals from the plant management staff; content of telephone and radio communications; transportation costs; maintenance of general plant buildings; business travel expenses; costs of training, etc.
Cost estimate for the annual volume of repairs work can be presented in the form of a table like this:
Table 5.1 – Cost estimate for the annual volume of repair work
WORK PROCEDURE AND REPORTING FORM:
Solve the problem using the given solution algorithm.
Example 1
Prepare a cost estimate for the annual volume of repair work based on the following initial data:
t k = 11 n/h – labor intensity of major repairs per standard repair unit;
t s= 5 n/h – labor intensity of an average repair per standard repair unit;
t m 1 n/h – labor intensity of minor repairs per standard repair unit;
n to=1 – number of major repairs in PPR schedule;
n with= 2 – number of medium repairs in the maintenance schedule;
n m= 5 – number of small repairs in the maintenance schedule;
Shopping center= 9.6 years – average duration of the repair cycle;
åNe= 712 rub. – total number of repair units.
Ksm=2 – number of equipment shifts per day;
N=1000 rubles – standard of service per worker per shift
A= 10% – percentage of lost working time;
Fн= 2026 hours – nominal time fund for the year.
Apt.n.= 1.05 ¸ 1.25 – coefficient of compliance with standards;
Np= 30 ¸ 40% – bonus standard according to the current bonus system taken from the collective agreement of AMZ OJSC.
Nd= 10 ¸ 15% – standard additional payments for deviation from normal conditions work.
Nvf= 30% – standard percentage of contributions to extra-budgetary funds.
materials costs amount to 140% of the main wage fund
overhead costs associated with organizing the management of the repair facility, which amount to 400%
Electrician's workplace
An electrician's workplace consists of a specially designed table, a swivel chair adjustable to different heights, special fixtures and devices, individual lighting, a local exhaust ventilation system, etc.
The electrician's table (Fig. 1) designed by N.A. Karasev and others is intended for performing work on cutting and terminating cables, manufacturing grounding jumpers, etc. in an electrical installation shop.
An electrician's table is a table with metal frame and panels made of light alloys. The working part of the table contains equipment and various devices for performing labor-intensive operations using automation, electronics and high-frequency technology: an electric hydraulic press for terminating cold crimp cables; ultrasonic device 3 for cleaning cable cores before soldering; wave machine for soldering tips and tinning busbars. An electronic “spine” device is mounted in the upper left desk drawer for identifying cores during marking. The remaining drawers of the electrician's desk contain tags, tips, tools, fixtures, electric soldering irons, instruments and various materials.
Rice. 1. Electrician's table.
Carrying out operations at the workplace allows you to reduce labor intensity by 40-50%, improve working conditions for electricians, ensure high quality installation and generally improve production standards.
In Fig. 2 shows a unified table designed for equipping workplaces for electrical and radio installers. The table frame is made of rectangular metal pipe and has rectangular shape, which greatly simplifies its production.
A large tabletop made of particle board, covered with laminated plastic on top. Two cabinets, also finished with laminated plastic, are fixed to the frame. The depth of the drawers of the cabinets is determined by the width of the large tabletop, which allows rational use of the volume of each drawer.
One of the elements of the electrician's table is a replaceable section. It consists of a small tabletop, a hanging panel, an air intake, an air duct and a bracket for hanging drawings. The small tabletop and wall panel are made of chipboard and finished with laminated plastic.
The air intake is made of impact-resistant polystyrene. The location of the air intake allows for rational use of the entire working surface of the table, as well as the most efficient suction of harmful emissions generated during soldering. The design of the air intake allows it to be rotated 360° around a vertical axis and adjusted in height. In order to more effectively suck out harmful emissions during soldering and create better sanitary and hygienic working conditions for installers, a pressurization device powered by the system is mounted on the table compressed air. By adjusting the air pressure and the position of the booster slot, you can create the necessary air flow towards the air intake. This air flow serves reliable protection installer from harmful fumes during soldering.
Rice. 2. Unified electrician's table.
Two lifting and rotating brackets for hanging drawings are mounted on the small tabletop. The top drawer of the table cabinet is used for mounting the power supply panel for the soldering iron and electric knife. On the front panel of this remote control there are knobs for regulating the heating temperature of the soldering iron and electric knife, an alarm light and a power switch. This arrangement of the power remote control is rational in design and convenient to use.
The design of the cabinet drawers makes it possible to install holders for tools and parts in accordance with the characteristics of the worker’s work.
Electrician's tables are installed four in a row. With this arrangement, a common power source is installed for the entire row. In addition, it is convenient for cleaning the room.
dimensions: 1300X730X750 mm.
To ensure maximum productivity and best quality During the work performed, it is necessary that all switching organs of devices, components and parts, materials, fixtures and installation tools are in the zone of working hand movements. Radioelements, materials, each tool and soldering iron must have their own specific place. Small radio components should be placed in numbered compartments of the cash register. After each operation, the tool must be placed in its designated place. The scales of measuring instruments must be placed in a vertical plane at eye level. There should be no foreign objects on the table. The workplace must be kept clean.
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Search LecturesMINISTRY OF EDUCATION AND SCIENCE OF THE UDMURT REPUBLIC
Autonomous professional educational institution
"Izhevsk Industrial and Economic College"
(APOU "IPEC")
TRAINING PRACTICE
PU.PM.02.13.01.10.2017.I230.000
PM. 02 “Checking and adjusting electrical equipment”
Completed
Student of group ER-15-1
"___" __________ 2017
LEADERS
Master p/o ____________I.V.Iteshin
GRADE ___________________
"___" ___________ 2017
1) Lead
Organization of an electrician’s workplace……. …………
2) Rules for electrical safety when using power tools………………………………………………………………….
3) Rules for providing first aid to a victim of electric shock…………………………………………………………………………………..
4) The sequence of work when soldering wires and cables. ………………………………………………………………………………….
5) List the devices, tools, and accessories needed when performing electrical installation work. …………………………..
6) Conclusion……………………………………………………………………………….
Organization of an electrician's workplace.
A workplace is a certain section of the production area of a workshop, assigned to a given worker (or team of workers), intended to perform certain work and equipped in accordance with the nature of the work with equipment, fixtures, tools and materials.
Electricians servicing electrical equipment often have to perform various plumbing and assembly operations. Therefore, they must clearly know the safety rules when carrying out such work and be able to organize their safe implementation. The organization of the workplace is the most important element in the organization of work. Right choice and placement of equipment, tools and materials in the workplace create the most favorable conditions work. Before starting work, you should check the condition of the tool that will be used to do it. A tool that has defects must be replaced with a serviceable one. The hammer must be firmly seated on the handle, which is wedged with a wedge made of mild steel or wood. You cannot correct a hammer with a weakened handle by hitting it against miles or other objects, this leads to even greater loosening of the handle. The handles of scrapers, files and other tools must also be firmly attached. Loosely fitted handles easily jump off the tool during operation, and the sharp shank of the tool can seriously injure your hand. Hand tools It is prohibited to use without a handle.
The labor movements of electricians, electricians and repairmen can be divided into five groups:
· finger movements;
movements of fingers and wrist;
· movements of fingers, wrist and forearm;
· movements of fingers, wrist, forearm and shoulder;
· movements of the fingers, wrist, forearm, shoulder and trunk.
To reduce fatigue, the worker’s movements should involve the smallest number of joints. Safety precautions require that a tool with defects be immediately replaced with a working one.
Proper organization of the workplace ensures rational movements of the worker and reduces to a minimum the amount of working time spent on finding and using tools and materials.
At the workplace of the shop electrician on duty there should be: Technological equipment of the workplace of the shop electrician:
Organizational equipment of the workshop electrician's workplace:
| Name of equipment | Characteristic |
| Workbench size 1600x800x750 mm | Consists of two cabinets, a tabletop, a desktop cabinet with spare parts and telephones, a desktop distribution board with a supplied voltage of 380 V and a removed voltage of 6, 12, 24, 36, 127 and 220 V, an alarm panel that allows you to call an electrician from the workshop by pressing a button |
| Mobile table size 1100x650x750 mm | Used for disassembling, cleaning, washing and assembling electrical installations. Serves as a vehicle for transporting cargo weighing up to 100 kg. Mounted on wheels with rolling bearings |
| Shelf cabinet size 1800x500x170 mm | Designed to store large fixtures and spare tools used in repairs |
| Portable tool bag | Used by the electrician on duty when carrying tools and measuring instruments |
| Chair-stool with a diameter of 400 mm | Consists of a rotating support, a seat and movable supports. The design takes into account the individual characteristics of workers and provides the most comfortable working position |
job description, electrical diagrams of the main electrical installations, power supply diagrams of the workshop or site, operational log, safety instructions, inspection schedules and shift-hour indicator-calendar of the electrician's location. The workplace must be designed in accordance with the requirements of technical aesthetics. The workplaces in which electrical workers work are different depending on what actions and operations they perform: installation, assembly, adjustment, etc. The electrician's workplace can be on outdoors, for example during the construction or repair of overhead and cable electrical networks, substations, etc. In all cases, there must be an exemplary order at the workplace: the tools of the device (only working tools are allowed to be used) must be placed in the appropriate places, the tool must also be put there after finishing work with it, there should be nothing unnecessary at the workplace that is not required for the task of this work, the equipment and maintenance of the workplace must strictly meet all labor protection, safety, industrial sanitation and hygiene requirements and exclude the possibility of a fire.
All of the above general requirements also apply to the student’s work must. It can be an assembly table or workbench (when performing electrical installation and insulating work), a winding machine (when performing winding work), a special workbench or table (when performing plumbing and assembly work), etc. Depending on the type of electrical work performed (installation, assembly, operation, etc.), the workplace must be equipped with appropriate tools and devices. Typically the following tools are placed at the workplace:
fastening and clamping pliers, round nose pliers, pliers, vices; cutting tools - mechanic's knife, wire cutters, hacksaw, impact hammer, chisel, punch. In addition, general metalworking tools are used, as well as many types of metal-cutting tools, since electrical work is often associated with cutting metal, bending pipes, cutting various materials, threading, etc.
Factories produce sets of tools for performing individual species electrical work. Each set is placed in a closed bag made of leatherette (IN-3) or in a folding bag made of artificial leather (NIE-3), the weight of the set is 3.25 kg. So, in a set of tools for performing electrical work general purpose includes the following: 200 mm universal pliers, electrical installation pliers with elastic covers; needle nose pliers (nippers) 150 mm with elastic covers; screwdriver for plumbing and installation, different (with plastic handles) - 3 pcs; mechanic's hammer with a handle weighing 0.8 kg; mechanic's knife; monter's awl; voltage indicator; meter folding metal ruler; light-colored safety glasses; plaster; ironer; twisted cord with a diameter of 1.5-2 mm and a length of 15 m.
While at work, strictly follow the following rules:
1 . Be attentive, disciplined, careful, accurately follow the oral and written instructions of the teacher (master)
2. Do not leave your workplace without the permission of the teacher (master).
3. Place instruments, tools, materials, equipment at the workplace in the order specified by the teacher (master) or in written instructions.
4 . Do not keep items in the workplace that are not required for the task.
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Organization of a workplace for electrical installation work
When organizing a workplace for electrical installation work, first of all, it is necessary to ensure safety and sanitary and hygienic working conditions. It is necessary to plan and equip the workplace so that the work is completed with the least amount of effort and time.
In general, a workplace is a part of the space that is adapted for performing electrical installation work.
A workplace for electrical installation work must consist of a specially designed table, a swivel chair that can be freely adjusted to different heights, individual lighting, a local exhaust ventilation system, as well as special fixtures, devices and tools.
The workplace must be kept clean and tidy and free from foreign objects. The illumination of the workplace must comply with current sanitary standards.
To perform any electrical work, you need a whole arsenal of electrical installation tools, as well as various electrical materials, such as installation wires, cords, insulating tapes, and tubes.
It is important to remember that any electrical installation tool, if used ineptly and incorrectly, can become a source of various injuries.
Let's look at the purpose and design of some basic electrical tools.
So, to perform electrical installation work you will need: an electrician's knife, side cutters, round nose pliers, pliers, pliers, pliers and various screwdrivers.
A mechanic's knife is used for removing paper and rubber insulation from wires and cables, as well as for stripping wires. The blade and bracket of the knife are made of tool steel. As a rule, the knife has a safety lock against arbitrary folding.
Please note that when stripping wires, the tip of the knife should be guided by hand, and the protected wire should not be held with your finger. If you press hard, the knife can remove not only the insulation, but also cut into the core material and cut your hand with shavings.
Side cutters are a tool used to cut (or, one might say, bite off) a wire with a small cross-section, and also remove the insulation from the wire. The cutters are sharp cutting edges.
Round nose pliers are used for terminating cores, wires and cables. In other words, they are used when you need to bend a wire to make a ring out of it.
Pliers are useful for bending, twisting wires and crimping their connections. The pliers have a serration on inside sponge
Pliers are combination pliers. They can both bite off, bend, twist wires, and also crimp the connected wire strands.
Pliers are great for stripping insulation.
Please note that when working with wire cutters, round nose pliers, pliers, pliers and pliers, you should never put your fingers between the handles. These tools need to be held tightly.
Screwdrivers. For normal operation you need to have several screwdrivers of different sizes. They are used for loosening and tightening screws. The metal parts of screwdrivers are made of hard steel, and the handles are made of wood or plastic, and they should not have cracks or chips.
Please note that when screwing in screws, the screwdriver should be held by the handle and shaft, and not supported by the screw being screwed, as the screwdriver may slip off the screw and injure your hand.
Installation of electrical circuits is carried out on tables, which must be covered insulating material.
For the convenience of electrical work, all tools and materials must be in a certain order. So, to the left of the electrician there should be materials prepared for installation, namely wires, switches, lamps, sockets, screws, nuts, washers, in front of the electrician there should be a mounting panel and an electrical diagram of the circuit, and to the right - all electrical installation tools. It will be convenient to place those tools that are used most often, such as wire cutters, pliers and screwdrivers, closer to you.
Now let's list the safety rules that we must strictly follow when doing electrical work.
Firstly, you must be attentive, disciplined, careful and accurately follow the teacher’s instructions.
Secondly, under no circumstances should you leave your workplace without the teacher’s permission.
Thirdly, at the workplace, instruments, tools, materials, equipment must be placed in the order indicated by the teacher.
Fourthly, there should be no items in the workplace that are not required to complete the task.
Fifthly, during work, only those materials or parts that will be mounted should be on the mounting panel.
Sixth, all electrical installation tools must have insulated handles.
Seventh, you can only work with a working tool.
Eighth, you need to serve the instrument with the handle facing away from you, and put it on the table with the handle towards you.
Ninth, it is necessary to handle tools and materials carefully and not drop them on the floor.
Tenth, electrical installation tools must be used strictly for their intended purpose.
Eleventh, the blade of the screwdriver should fit tightly into the slot of the screw.
Twelfth, it is prohibited to use a screwdriver while suspended. You must hold the screwdriver away from you.
Thirteenth, order must be maintained in the workplace. Tools and materials must be in the designated areas.
And, fourteenth, the connection points and branches of the wires must be reliably insulated.
And it will also be useful to remember electric current and discuss all its dangers.
As you already know, electric current can not only bring benefits to a person, but also pose a serious danger to him.
After all, the human body is a conductor of electric current. And if suddenly, by some chance, a person’s body becomes energized, then in fact, the person will become an element of an electrical circuit.
Moreover, the damaging effect of electric current will directly depend on the magnitude of the current, the path of its passage through the body and the time of passage. In this case, the current strength depends on the magnitude of the applied voltage and the resistance of the human body.
Scientists have already proven that different tissues of the human body resist electric current in different ways, that is, they have different resistance.
Thus, skin, bones and adipose tissue have great resistance to electric current, but muscle tissue, blood, spinal cord and brain have little resistance. Human skin, especially its top layer, has the greatest resistance.
If a person has dry and clean skin, then the electrical resistance of the body at a voltage of 15–20 volts can vary from 3,000 to 100,000 ohms.
If the skin has damage, for example, scratches, cuts, bruises, as well as sweating, then the body resistance decreases to 300–500 ohms. With prolonged current flow, skin resistance also decreases.
A person begins to feel the impact of electricity passing through him at an alternating current of 0.001–0.0015 A. This current is called threshold-perceptible.
At a current of 0.01–0.015 A, a person will no longer be able to independently tear his hands away from the electrodes. By the way, such a current is called non-releasing current. In this state, a person needs outside help. And the outcome will depend on the duration of the current exposure.
With prolonged exposure, the current strength, increasing, can lead to damage to the respiratory system and heart.
The best help in such a situation is to turn off the power source, while insuring the victim from falling to the floor. If the power supply switch is located far away (outside the classroom), then the victim must be separated from the electrodes using an insulator. This could be a stick, board, belt, scarf, or grab clothing.
It is important to remember that under no circumstances should you touch the body of a person who is under voltage.
Since this is very dangerous, the rescuer himself may find himself in the position of a victim.
A current of 0.05 A is dangerous to human life. If the current flows for a long time through a person's hands, through arms and legs, or through the legs, the current leads to heart damage and cardiac arrest.
In this condition, the victim must be quickly disconnected from the power source and given emergency assistance. It is necessary to perform cardiac massage and artificial respiration. If this is not done, death will occur within 5–7 minutes.
Dangerous voltage for human life is 50 volts.
At school, for most practical work in electrical engineering, DC sources with a voltage of 4–4.5 V are used. This voltage is completely safe for humans. True only if we are talking about galvanic direct current sources in the form of a battery from a flashlight.
With secondary DC sources that are connected to a 36 or 42 volt AC network, you should be more careful. Particular vigilance is required when working with 42 volts. 42 volt alternating voltage significantly reduces, but does not eliminate, the danger of injury electric shock. In the human body at such a voltage, the effect of a non-releasing current can occur with all life-threatening consequences.
Remember safety rules when working with 42-volt AC sources.
Installation and disassembly of all electrical circuits must be carried out only when the power source is turned off.
The AC source can only be turned on after the teacher has checked the electrical circuit you have assembled.
After the current source is turned on, it is strictly forbidden to touch the elements of the assembled electrical circuit with your hands, especially the electrodes that are connected to the outputs of the source.
Lesson summary
In this lesson, we discussed how to properly organize a workplace during electrical work. We looked at the purpose and design of some electrical tools that may be needed to perform electrical work. We have listed the safety rules that we must strictly follow when performing electrical work. We also talked about the dangers that electric current poses to human life.
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Requirements for an electrician's workplace
The electrician's desk should also have an ergonomic and functional design aimed at reducing labor costs and the time required to perform certain operations.
General requirements for the workplace
Proper organization of the workplace helps to increase labor productivity - a well-known fact. Choosing an installer's workplace from a ready-made metal furniture There is no doubt that all models are designed taking into account the requirements for comfort and are able to create an optimal working environment for the employee.
For reasons of personal safety, the table must be kept clean, everything necessary equipment be correct and working surface freed from foreign objects.
Since an electrician deals with sensitive, expensive electronics, a number of requirements are put forward for the antistatic properties of all surfaces that the technician comes into contact with during work, and for his clothing.
Design features of an electrician's table
The workplace is metal table, made of light and durable alloys with a dielectric and heat-resistant tabletop (its role can be played by a sheet of textolite). Various devices and equipment for performing high-precision operations can be mounted or arranged arbitrarily on the table surface. On the shelves of the superstructure, in the drawers of the built-in cabinet, boards, microcircuits, tags, hand tools, materials and components necessary for work can be stored in order.
The electrician's desk must be grounded and equipped with:
- Electrical wiring with a mains voltage of up to 36 V (it is necessary to power lighting, soldering iron, analysis and control tools).
- Autotransformer for smooth adjustment of the supplied voltage.
- Sufficient for long-term work with small details and at the same time unobtrusive lighting
- Exhaust system ventilation to remove combustion products when working with soldering.
The master works mainly with small radio components and installation tools; they will help create an extremely convenient, organized storage system, such as this one additional accessories– containers, boxes, lodgements, etc. On the workbench, all tools should be located so that the electrician makes the bulk of movements with minimal labor, within the normal working area (at arm's length).
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Construction machines and equipment, reference book
Tool for electrical work
Requirements for organizing workplaces
When organizing an electrician's workplace, it is necessary first of all to ensure safety and sanitary and hygienic working conditions. The workplace should be planned and equipped so that work is completed with minimal effort and time.
The workplace in an enterprise plays a special role. A well-organized workplace contributes to the economical use of production space, compliance with technological discipline and improved product quality. Proper organization of an electrician's workplace ensures an increase in labor productivity. The significant growth in production and the widespread introduction of mechanization and automation place special demands on the organization of workplaces and their maintenance.
The electrician's workplace must be kept clean and tidy and free from foreign objects. The electrician's desk should be comfortable, with adjustable height seats and backs. The illumination of the workplace must comply with current sanitary standards.
The workplace must be equipped with an electrical supply with a voltage of no more than 36 V to power the lighting lamp, electric soldering iron and control equipment; an autotransformer for smooth regulation of the soldering iron supply voltage and an installer’s device; exhaust ventilation system.
The electrician's workplace must be equipped with a technological map of the corresponding installation operation or an installation diagram and a set of tools and accessories. All components, parts, materials, and installation tools must be placed at the workplace so that they are convenient to use during work. Small radio components and workpieces must be placed in the cells of cash register boxes. Organizational and technological equipment, tools and devices should be positioned so that the greatest number of movements are made within the normal working area.
The given recommendations for the organization and maintenance of workplaces do not reflect all possible options for the rational organization of workplaces in the specific operating conditions of various enterprises. The organization of workplaces and their maintenance at each specific enterprise must be decided taking into account the production conditions, complexity and level of mechanization of the work performed.
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Construction machines and equipment, reference book
Tool for electrical work
Equipment for an electrician's workplace
Stand for wiring diagrams and drawings. In the production of radio-electronic equipment, an increase in labor productivity is impossible without the introduction of advanced methods and techniques, without further improving the system of servicing workplaces based on the scientific organization of production. In this regard, equipping workplaces with modern high-performance equipment is of paramount importance.
In order to install a radio-electronic device at a high technical level, the electrician must strictly follow all the instructions in the installation diagram. And here the question immediately arises: where to keep the wiring diagram so that it is convenient to use? You can put the wiring diagram on your desktop, but it takes up a lot of space.
This issue is solved by a simple design and convenient stand for mounting wiring diagrams and drawings (Fig. 1), developed by the author. The device consists of a cylindrical base made of duralumin, on which an aluminum thin-walled tube is attached using a thread, a movable special bushing for attaching two movable holders, hooks and a stop.
Rice. 1. Stand for mounting wiring diagrams and drawings.
This device allows you to attach large diagrams and drawings, makes it possible to zoom in and out of the drawing, move it to the left or right of the center, depending on the illumination of the workplace. A telescopic stand can be made for the stand, which can be easily installed at a height convenient for the electrician. The use of such a stand creates convenience in the work of electrical and radio installers and improves the culture of their workplace.
Cylindrical cash register for radioelements and fasteners. During assembly and electrical installation work, various types of fastening of radio elements, marking tags, etc. are used. At the workplace, these parts are usually kept in special boxes with cells. This method of placement has a number of disadvantages: the parts collect dust, they are easy to mix up when removed, and they also take up a large area in the workplace.
Rice. 2. Cylindrical rotary cash register.
The most convenient devices are cylindrical rotary cash registers (Fig. 2), introduced into production by the innovator S.V. Vorobyov. All structural elements of the cash register are located on a vertical axis, the lower end of which is fixed in a massive steel base. Between the base and the cover there are sixteen segments located on the axis, each of which can rotate independently of the others. The segments are made of ebonite. For ease of use, a tag with the name of the stored parts is affixed to each segment.
Cash register diameter 180 mm; height 230 mm; weight 2 kg.
Mounting accessory printed circuit boards. Electrical installation is one of the most critical types of radio-electronic equipment and largely determines its reliability and performance.
Carrying out electrical work on printed circuit boards is greatly facilitated by using a universal device.
The device consists of a disk-shaped base, which ensures rotation of the body mounted on it. Grooves are milled on the body to provide fastening of the racks, which can move along the groove of the body and be secured with screws in the desired position. The circuit board is clamped with clamping jaws, which are mounted on stands connected to movable axles and handles.
The board can be rotated 360° using the handles. The racks move along the groove and are attached at the required distance depending on the size of the mounting plates.
The design of the device is simple to manufacture and convenient to install. Overall dimensions: 300Х 140Х XI30 mm; weight 5 kg.
The optical mounting device (Fig. 4) is designed to perform a number of jobs related to the assembly of small parts of precision mechanisms and instruments, mounting and soldering of microcircuit pins, etc.
Rice. 3. Device for mounting printed circuit boards.
Rice. 4 Optical mounting device.
The device consists of a cylindrical massive base on which a vertical rod is fixed. The lens is installed in a holder, which is hinged in an arched bracket equipped with a sleeve that moves along the rod. A table is mounted on the rod, on which products are placed to perform the appropriate installation or assembly of products. The main part of the device is a viewing plano-convex lens that provides four times magnification. The lens is long-focus, which allows you to place the object in question at different distances from it while maintaining the required image sharpness.
The presence of a ring around the lens fluorescent lamp type LBK-20, covered with a reflector, creates shadowless illumination of the mechanism. The device is simple in design and easy to use.
A pneumatic blowing vacuum cleaner, developed by the innovator N. N. Vasiliev, is designed for collecting dust, small chips, various small waste and for cleaning parts, parts and products from dust by blowing hard to reach places when processing parts of complex configuration and other assembly work.
The vacuum cleaner-blower consists of a body with a handle made of press powder brand K18, a suction pipe made of a thin-walled duralumin tube with a diameter of 20 mm, an adjustable ejector, a valve with a trigger, a dust collector made of cast rubber, a brass mesh 6 and a duralumin fitting. By adjusting the ejector and the size of the gap in it, you can set the required vacuum in the pipe, creating sufficient draft for sucking in small industrial waste and blowing products.
The blower vacuum cleaner is turned on using a valve with a trigger. The compressed air supply is made by a flexible rubber hose connected to the handle through a special fitting. The compressed air pressure in the pneumatic network should be 4 kgf/cm2.
Rice. 5. Pneumatic vacuum cleaner-blower.
The blowing vacuum cleaner is easy to use and small in size. Its mass is 0.18 kg.
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Electricians servicing electrical equipment often have to perform various plumbing and assembly operations. Therefore, they must clearly know the safety rules when carrying out such work and be able to organize their safe implementation. Before starting work, you should check the condition of the tool that will be used to do it. A tool that has defects must be replaced with a serviceable one. The hammer must be firmly seated on the handle, which is wedged with a wedge made of mild steel or wood. You cannot correct a hammer with a weakened handle by hitting it against miles or other objects, this leads to even greater loosening of the handle. The handles of scrapers, files and other tools must also be firmly attached. Loosely fitted handles easily jump off the tool during operation, and the sharp shank of the tool can seriously injure your hand. It is prohibited to use hand tools without a handle. Spanners must match the dimensions of the nuts and bolt heads; It is not allowed to use keys with wrinkled or cracked jaws, to extend keys with pipes, other keys or in any other way; it is necessary to monitor the serviceability of the vice and pullers. Proper organization of the workplace ensures rational movements of the worker and reduces to a minimum the amount of working time spent on finding and using tools and materials. At the electrician's workplace there should be: technological equipment, organizational equipment, job descriptions, electrical diagrams of the main electrical installations, power supply diagrams, an operational log, and safety instructions. A workplace is a part of space adapted for an employee to perform a production task. The workplace, as a rule, is equipped with main and auxiliary equipment (machines, mechanisms, power plants, etc.), technological equipment (tools, fixtures, instrumentation). The workplaces in which electrical workers work vary depending on what actions and operations they perform: installation, assembly, adjustment, etc. An electrician’s workplace can also be outdoors, for example, during the construction or repair of overhead and cable electrical networks, substations, etc. In all cases, there must be an exemplary order at the workplace: the tools of the device (only working tools are allowed to be used) must be placed in the appropriate places, the tool must also be put there after finishing work with it, there should be nothing unnecessary at the workplace that is not required for the task of this work, the equipment and maintenance of the workplace must strictly meet all labor protection, safety, industrial sanitation and hygiene requirements and exclude the possibility of a fire. Typically, the following tools are placed at the workplace: fastening and clamping tools - pliers, round nose pliers, pliers, a vice; cutting tools - mechanic's knife, wire cutters, hacksaw, impact hammer, chisel, punch. In addition, general metalworking tools are used, as well as many types of metal-cutting tools, since electrical work is often associated with cutting metal, bending pipes, cutting various materials, threading, etc. Factories produce sets of tools for performing certain types of electrical work. Each set is placed in a closed bag made of leatherette or in a folding bag made of artificial leather, the weight of the set is 3.25 kg. Thus, the set of tools for performing general-purpose electrical work includes the following: 200 mm universal pliers, electrical installation pliers with elastic covers, 150 mm needle-nose pliers (nippers) with elastic covers; screwdriver for plumbing and installation, different (with plastic handles) - 3 pcs; mechanic's hammer with a handle weighing 0.8 kg; mechanic's knife; monter's awl; voltage indicator; meter folding metal ruler; light-colored safety glasses; plaster; ironer; twisted cord with a diameter of 1.5-2 mm and a length of 15 m. The electrician's job responsibilities are presented in Appendix D. | |
Introduction
Manufacturing process
Types of production:
1. Individual
2. Serial
3. Mass
Wiring table
Wiring table
Materials and products
Cables and wires are used for channeling (transfer and distribution) of electrical energy, as well as for connecting various elements electrical installations. Cables are divided into power and control.
Cable consists of one or more insulated conductors enclosed in a sealed (metallic or non-metallic) sheath, on top of which, depending on the laying and operating conditions, there may be armor and protective coverings.
The main elements of cables are conductors, insulation, sheath, armor and outer covers. Depending on the purpose and operating conditions of the cables, individual elements in their design may be missing. The conductors are made of aluminum and copper.
Conducting copper is a reddish-orange metal purified from various impurities with a melting point of 1083 ° C and a linear temperature coefficient of expansion equal to 17-10 6 1 / ° C. Copper has good mechanical properties and ductility, which makes it possible to produce wire with a diameter of 0.03 ... 0.01 mm, as well as thin strips. Conductor copper is very resistant to atmospheric corrosion, which contributes to thin layer oxide with which it is coated in air and which prevents further penetration of oxygen into it.
The domestic industry produces six grades of conductor ground with varying degrees of purity. Impurities in copper include bismuth, antimony, iron, lead, tin, zinc, nickel, phosphorus, sulfur and oxygen. For the manufacture of conductor products (winding and installation wires and cables), grades of conductor copper with an impurity content of 0.05...0.1% are used.
Copper wire of small diameter has a high tensile stress and a high specific electrical resistance. For wires of very small diameter (0.01 mm) intended for operation at elevated temperatures (above 300 ° C), wire made of oxygen-free copper, which is characterized by the highest purity, is used. Temperature coefficient of resistivity ТК=0.0043 1/°С for all grades of copper.
Aluminum is the second conductor material after copper due to its relatively high conductivity and resistance to atmospheric corrosion. In air, aluminum very quickly becomes covered with a thin film of oxide, which reliably protects it from the penetration of oxygen. At the same time, this film has significant electrical resistance, so in poorly cleaned joints of aluminum wires there may be high transition resistances.
For electrical insulation of cores For cables, impregnated cable paper, rubber, and plastic (polyvinyl chloride, polyethylene, etc.) are used.
cable paper is the main insulating material used in high voltage cables. After winding the cable, it is impregnated with electrical insulating oil.
Cable paper is produced from sulphate cellulose, predominantly of fat milling, in order to ensure high mechanical strength, as well as high density and low porosity. The liquid substance (oil or oil-rosin composition) is broken by the paper during impregnation into thin films and channels, increasing its electrical strength. Cable paper is produced for core insulation power cables, designed for voltages of 35, 110 and 220 kV.
Characteristic property everyone rubber is their great elasticity, i.e. ability to greatly elongate when stretched!
Polyethylene- a hard, opaque material of white or light gray color, somewhat greasy to the touch. This is a thermoplastic material supplied to factories in the form of granules. Polyethylene products are produced using injection molding methods.
The insulation of wires and cables made of irradiated polyethylene is characterized by increased heat resistance (up to 100 ° C) and mechanical strength.
Polyvinyl chloride is a powder white, from which mechanically strong products (boards, pipes, etc.) that are resistant to impact are obtained by hot pressing or hot extrusion mineral oils, many solvents, alkalis and acids. By hot pressing powdered polyvinyl chloride, a hard, rigid material is obtained - vinyl plastic in the form of sheets, plates, pipes and rods, which have high mechanical strength and good electrical insulating properties.
Cable sheaths can be lead, aluminum, rubber, plastic. They protect the insulation of current-carrying conductors from exposure to light, moisture, chemical substances and other factors environment, as well as from mechanical damage.
The following designations are used in cable brands: sheath - C (lead), A (aluminum), N (non-flammable rubber). B (polyvinyl chloride); protective coating - B (armor made of tapes).
Fig.3.1 Four-core cable
P (flat wire armor); absence of outer cover - G (naked), and they may also contain letters indicating the presence of other structural elements. For example, if the brand begins with the letter O, this indicates the presence of separately leaded conductors in the cable. Cables with copper (aluminum) conductors:
VVG (AVVG) - with polyvinyl chloride insulation and sheath;
PVG (AGOG) - with polyethylene insulation and polyvinyl chloride shell;
VVB (AVVB) - with polyvinyl chloride insulation and sheath, armored with steel strips with an outer cover:
PVB (APVB) - with polyethylene insulation and polyvinyl chloride sheath, armored with steel strips with an outer cover.
The wire It represents one uninsulated core or one or more insulated cores, on top of which, depending on the laying and operating conditions, there may be a non-metallic sheath and metallic or non-metallic protective covers.
Wires are divided into insulated and non-insulated, protected and unprotected. Uninsulated (bare) wires, used mainly for laying air lines, can be aluminum, steel-aluminium, copper, bronze and steel. Insulated wires can only have aluminum and copper conductors. Rubber and plastic are used as electrical insulation of wire cores.
To protect against mechanical influences, light and moisture, the wires are covered with a sheath of rubber, plastic or metal tapes with a folded seam:
Cord consists of two or more insulated flexible or especially flexible conductors, twisted or laid in parallel, on top of which, depending on operating conditions, there may be a non-metallic sheath and protective covers. Cords differ from wires in the flexibility of stranded cores.
In the marking of wires and cords, the first letter A indicates the material of the conductor is aluminum (the absence of the letter A means that the conductor is made of copper). The second letter P denotes the wire, and the third - the insulation material (P - rubber, B - polyvinyl chloride, P - polyethylene). The brands of wires and cords may also contain other letters, for example: O - braid, X - laying in pipes, P - flat element with a dividing base, F - folded metal sheath, G - flexibility, etc.
Wires and cables are distinguished by the number and cross-section of cores, as well as rated voltage. The number of cores can be from one to four (control cables have from four to thirty-seven cores); and sections from 0.75 to 600 mm 2. The following core sections are standard: 0.5; 0.75; 1; 1,5,2,5; 4; 6; 10; 16; 25; 35; 50; 70; 95; 120; 150; 185; 240; 300; 400; 500; 625 and 800 mm 3.
Wires are manufactured for voltages of 380, 660 and 3000 V AC, cables for all standard voltages up to 110 kV.
INSTALLATION OF ELECTRIC WIRING
Cable continuity.
For correct connection Contact cables of electrical machines, instruments and apparatus are tested. The simplest dialing is done using lamps and a battery, i.e. The conductors of one cable are randomly marked and a battery wire is connected to the first of them, then a conductor is connected to the lamp and the conductors at the other end of the cable are touched one by one. If the lamp lights up when touched, it means that this is the core to which the battery wire is connected. To mark the cores of power cables, use pieces of vinyl tubes or special ends on which inscriptions are made in indelible ink
Cable testing diagram: a, b – using a lamp; c – using telephone handsets; d – using a special transformer
Introduction
Manufacturing process- is a set of actions aimed at producing finished products.
Types of production:
1. Individual- this is a production where finished products are produced in units, employing generalists.
2. Serial- this is a production where the production of finished products is carried out in series and batches.
3. Mass- this is a production where finished products are produced in large quantities.
Organization of an electrician's workplace.
Electrician's workplace- this is a section of the production area of a workshop, a workshop assigned to a given student, designed to perform a specific job and equipped in accordance with the nature of this work with equipment, tools and materials.
Rational organization of the workplace- this is the organization of the workplace in which, with the least expenditure of effort and labor, safe working conditions are ensured and highest performance and high quality products.
The workplace is equipped with an electrical installation table, on which the tools, devices, and materials necessary for work are laid out.
Wiring table- is the main type of equipment for the execution workplace handmade and is a special table on which work is performed.
Wiring table
I. General requirements labor protection
1.1 Guidelines for performing electrical installation work
teachers, masters, students are admitted who have undergone occupational safety instruction, medical examination and have no contraindications for health reasons
1.2 Students must comply with the rules of behavior, established work and rest schedules.
1.3 When performing electrical installation work, workers may be exposed to the following hazardous and harmful production factors
¾ electric shock when touching bare wires and when working with live devices;
¾ hand injury when using a faulty tool;
¾ soldering of parts and wires using tin-lead solders.
1.4 When performing electrical installation work, the following special clothing and personal protective equipment must be used: a cotton robe, a beret, dielectric gloves, a dielectric mat, a voltage indicator and a tool with insulated handles.
1.5 In the room for electrical installation work there must be a first aid kit with a set of necessary medications and dressings.
1.6 Students are required to follow the rules fire safety, know the location primary funds fire extinguishing There must be a fire extinguisher and a sandbox in the room for electrical installation work.
1.7 In the event of an accident, the victim or eyewitness to the accident is obliged to immediately inform the teacher, the foreman, who informs the college administration about this. If equipment or tools malfunction, stop working and inform the teacher or foreman about it.
1.8 During work, follow the rules of wearing special clothing, using individual and collective protective equipment, observe hygiene rules, and keep the workplace clean.
1.9. Students who fail to comply with or violate labor safety instructions are held accountable, and all students are given unscheduled instruction on labor safety.
II. Labor safety requirements before starting work.
2.1 Put on overalls and carefully tuck your hair under your beret.
2.2 Check the condition and serviceability of equipment and tools.
2.3 Prepare the materials and equipment necessary for work and put them in their places, remove everything unnecessary from the table.
2.4 Prepare personal protective equipment for work and make sure they are in good working order.
2.5 When soldering parts and wires using tin-lead solders, turn on exhaust ventilation.
III. Requirement for labor protection during work.
3.1 It is prohibited to supply voltages higher than 42V AC and 110V DC to student desks.
3.2 It is necessary to assemble electrical circuits and make switches in them only in the absence of voltage. Connect the current source last.
3.3 Assemble electrical circuits so that the wires do not stop, are not stretched, and are not twisted into loops.
3.4 When soldering, use only rosin as a flux; it is prohibited to use acid.
3.5 Turn on the assembled electrical circuit under voltage only after checking it by a teacher or foreman.
3.6 When working with electrical devices and machines, ensure that hands, clothing and hair do not come into contact with rotating parts and exposed wires
3.7 Do not check for voltage by touching your fingers; use a voltage indicator for this.
3.8 Do not leave unattended electrical devices unattended.
3.9 Strictly follow the instructions on labor protection when electrical soldering.
IV. Occupational safety requirements in emergency situations.
4.1 If you find damaged electrical wiring, malfunction of equipment, devices, immediately turn off the power and inform the teacher about it.
4.2 If electrical equipment catches fire, immediately turn off the switch and begin extinguishing the fire with carbon dioxide, powder fire extinguisher or sand.
4.3 If injured, provide first aid to the victim, if necessary, send him to the nearest medical facility and inform the college administration about this.
V. Labor protection requirements upon completion of work.
5.1 Disconnect the electrical current circuit.
5.2 Put the workplace in order, store equipment and tools.
5.3 Carry out wet cleaning room and turn off the exhaust ventilation. Remove protective clothing and wash your hands thoroughly with soap.
Electricians servicing electrical equipment often have to perform various plumbing and assembly operations. Therefore, they must clearly know the safety rules when carrying out such work and be able to organize their safe implementation.
Before starting work, you should check the condition of the tool that will be used to do it. A tool that has defects must be replaced with a serviceable one. The hammer must be firmly seated on the handle, which is wedged with a wedge made of mild steel or wood. You cannot correct a hammer with a weakened handle by hitting it against miles or other objects, this leads to even greater loosening of the handle. The handles of scrapers, files and other tools must also be firmly attached. Loosely fitted handles easily jump off the tool during operation, and the sharp shank of the tool can seriously injure your hand. It is prohibited to use hand tools without a handle.
Wrenches must match the size of the nuts and bolt heads; It is not allowed to use keys with wrinkled or cracked jaws, to extend keys with pipes, other keys or in any other way; it is necessary to monitor the serviceability of the vice and pullers.
Proper organization of the workplace ensures rational movements of the worker and reduces to a minimum the amount of working time spent on finding and using tools and materials. At the electrician's workplace there should be: technological equipment, organizational equipment, job descriptions, electrical diagrams of the main electrical installations, power supply diagrams, an operational log, and safety instructions.
A workplace is a part of space adapted for an employee to perform a production task. The workplace, as a rule, is equipped with main and auxiliary equipment (machines, mechanisms, power plants, etc.), technological equipment (tools, fixtures, instrumentation).
The workplaces in which electrical workers work vary depending on what actions and operations they perform: installation, assembly, adjustment, etc. An electrician’s workplace can also be outdoors, for example, during the construction or repair of overhead and cable electrical networks, substations, etc.
In all cases, there must be an exemplary order at the workplace: the tools of the device (only working tools are allowed to be used) must be placed in the appropriate places, the tool must also be put there after finishing work with it, there should be nothing unnecessary at the workplace that is not required for the task of this work, the equipment and maintenance of the workplace must strictly meet all labor protection, safety, industrial sanitation and hygiene requirements and exclude the possibility of a fire.
Typically, the following tools are placed at the workplace: fastening and clamping tools - pliers, round nose pliers, pliers, a vice; cutting tools - mechanic's knife, wire cutters, hacksaw, impact hammer, chisel, punch. In addition, general metalworking tools are used, as well as many types of metal-cutting tools, since electrical work is often associated with cutting metal, bending pipes, cutting various materials, threading, etc. Factories produce sets of tools for performing certain types of electrical work. Each set is placed in a closed bag made of leatherette or in a folding bag made of artificial leather, the weight of the set is 3.25 kg. Thus, the set of tools for performing general-purpose electrical work includes the following: 200 mm universal pliers, electrical installation pliers with elastic covers, 150 mm needle-nose pliers (nippers) with elastic covers; screwdriver for plumbing and installation, different (with plastic handles) - 3 pcs; mechanic's hammer with a handle weighing 0.8 kg; mechanic's knife; monter's awl; voltage indicator; meter folding metal ruler; light-colored safety glasses; plaster; ironer; twisted cord with a diameter of 1.5-2 mm and a length of 15 m.
The electrician's job responsibilities are presented in Appendix D.
mobile table; Workbench; wardrobe - shelving; portable bag
Technical and accounting documentation is located at the workplace.
technical documentation - electrical circuits of the most complex machines, handling equipment, workshop power supply circuits, etc.
accounting documentation - operational journal, safety instructions for an electrician.
2. Maintenance and repair of power transformers.
A transformer is a static electromagnetic device that converts alternating current one voltage into alternating current of the same purity, but a different voltage.
The action of the transformer is based on the phenomenon of electromagnetic induction.
Power transformer - a transformer used to convert electricity in electrical networks and in installations intended for its use.
Maintenance of power transformers consists of periodic inspections of transformers.
When inspecting power transformers, check the readings of thermometers and pressure and vacuum gauges; condition of transformers; no oil leakage; the presence of oil in the oil of inhalations; oil level in the expanders, condition of insulators, spikes and cables, lack of heating of contact connections, condition of the grounding network.
3. Damaging factors of electric current acting on the human body.
Electric shock to a person is affected by the amount of current passing through his body, the type of current, the frequency, the path of the current, the duration of its exposure, the environment (humidity and air temperature. In case of electric shock, the main factors are the path of the current through the human body and the time of its exposure .
Ticket No. 7.
1. Current transformers, operating principle, main feature.
A current transformer is a transformer in which, under normal conditions of use, the electric current is practically proportional to the primary current and, when turned on correctly, is moved in phase with respect to it at an angle close to zero.
According to the magnitude of the error, current transformers are divided into 5 accuracy classes 0.2;0.5;1;3;10.
Current transformers:
0.2 precision laboratory measurements
0.5 - for powering electricity meters
1-for power supply of wattmeters, meters, panel devices.
3-for power supply of protection relays, devices, indicating devices.
10 - transformers of classes 1-3 are not specially manufactured in this class.
2. Classification of measuring instruments, measuring instruments.
Measurements - finding the value of a physical quantity experimentally using special technical means.