Describe the types of repair of household appliances and machines. Household machines and appliances, their maintenance. Maintenance and repair system
Repair and maintenance of household machines and appliances, watches, radio-electronic equipment, televisions, tape recorders, music centers, repair and manufacture of metal products, jewelry provide consumers with the opportunity to restore the consumer properties of used products or purchase new products created according to their individual order.
Services are provided in service technical centers and repair shops. Service centers and workshops for the repair and maintenance of household appliances, watches, radio-electronic equipment have premises for receiving visitors, workshops for repair and maintenance, a warehouse for storing repaired products, spare parts and parts, and an administrative building.
Customer service is performed by the receiver, who draws up an application and accepts the product for repair, or operators of the service for receiving applications by phone, via the Internet and by mail.
Repair services are performed by a repairman with a visit to the consumer's home or in a hospital. Consumers can deliver products for repair on their own or use the delivery services of a service center. When products are accepted for repair, malfunctions of the device are recorded, a contract for repair or maintenance is drawn up, and the deadline for fulfilling the order is specified.
If the service is performed at the consumer's home, then the contract and repairs are performed by the repairman. He diagnoses the device, identifies the main malfunctions and their causes. According to the diagnostic results, the type of repair is assigned.
If the repair includes the replacement of faulty parts and assemblies, the restoration of worn parts and assemblies, the components used for replacement must be provided for by the regulatory documentation for the device. Components included in the list of products subject to mandatory certification must be certified.
Technological equipment must be certified, measuring instruments and tools verified or calibrated.
Large service enterprises have several shops (for example, a shop for the repair of household machines and appliances, a shop for the repair of transformers). The workshops have production departments: dismantling and troubleshooting, mechanical repair, winding, drying and impregnation, picking, testing station, as well as separate sections where specific types of work are performed to repair transformers, household machines and appliances, appliances and switching devices. In the dismantling and troubleshooting department, the repaired goods are cleaned of contamination, oil is drained from transformers and oil-filled devices, pre-repair tests are performed, electrical equipment is dismantled, troubleshooting is carried out (the condition and degree of wear of individual parts are determined, as well as the scope of the upcoming repair, a defect list and a repair route map are drawn up , hang marking tags on the parts to be repaired, take measures to preserve serviceable parts of electrical appliances), transfer faulty parts to repair areas, and serviceable parts to the picking or assembly department.
The dismantling and troubleshooting department is equipped with lifting and transport vehicles, testing equipment or stands for pre-repair tests, washing baths, pullers, fixtures and tools for disassembling repaired household machines and appliances.
In the mechanical repair department, they repair and, if necessary, manufacture new parts of household machines and appliances (shafts, collectors, brush mechanisms, plain bearings), remix the cores of the rotors and stators of electrical machines and devices, unload the magnetic cores of transformers. This department is equipped with hoisting and transport vehicles, metalworking machines, presses, welding machines, tools and special devices.
If it is necessary to perform work on chrome plating and nickel plating of parts, galvanic baths are installed in a separate room.
In addition to the above equipment, the mechanical repair department has locksmith workbenches, racks and cabinets for storing parts and tools. In the winding department, damaged ones are repaired (insulation is restored) and new windings of electrical machines and devices, transformers and coils of electrical devices are manufactured.
The department is equipped with machines for winding and insulating windings and coils, a machine for making wedges, guillotine shears for cutting insulating materials, machines for shrouding rotors and armatures of electrical machines, welding and soldering tools for connecting winding wires, a test facility for step-by-step control of the insulation of produced windings, as well as devices for monitoring the correct connection of winding circuits.
If necessary, install (in a separate room with ventilation devices and fire extinguishing equipment) an oven for annealing wires, a bath for pickling them and a machine for drawing and calibrating wires of the old winding. Drying-impregnating department is used for impregnation and drying of manufactured windings. Its equipment includes impregnating baths, ovens for drying and baking impregnated windings, hoisting and transport vehicles for transporting massive windings and containers for storing impregnating varnishes and solvents in quantities that provide no more than a daily requirement for them. Given the harmfulness of vapors and volatile particles of varnishes and solvents, their high fire and explosion hazard, the premises of this department are provided with exhaust ventilation devices and fire extinguishing equipment.
The assembly department is the place where all repaired, as well as serviceable and some new assembly units and parts of the repaired equipment are delivered. Fully equipped electrical equipment is then transferred to the assembly department. In the assembly department, the general assembly of the repaired equipment is carried out. It is equipped with assembly tools and devices, workbenches and racks, devices for static and dynamic balancing of rotors and armatures of electrical machines, a test bench for performing the entire range of post-repair tests. The test station is located in a separate room and contains high-voltage test electrical installations, stands, various devices and protective equipment. The electrical repair shop includes warehouses for storing the repair fund (individual units and assembly units of electrical equipment: high and low voltage windings of transformers, contact system kits for switches, etc.) and repaired equipment, tool and material storerooms, utility and utility rooms, as well as other premises, the number and purpose of which are determined in each case by the adopted technology and repair conditions.
The organization of the workplace of a master in the repair of household machines and appliances has its own characteristics.
To perform services for the repair of household machines and appliances, the service company uses the main and additional equipment (machines, mechanisms, installations), technological equipment, fixtures, tools and necessary equipment (setting tables, workbenches, racks, cabinets). When organizing workplaces, service specialists must comply with the requirements of GOST for the creation of healthy and safe working conditions for electricians (lighting, personal protective equipment, primary fire extinguishing equipment, etc.).
Locksmith operations in the repair of household machines and appliances are performed using locksmith, metal-cutting and measuring tools. The set of basic locksmith tools includes hammers, chisels, files, screwdrivers, wrenches, hand saws. Of the metal-cutting tools, drills, countersinks, reamers, taps, and dies are primarily used. Of the measuring instruments, when marking, processing and manufacturing workpieces and parts, calipers, micrometers, gauges, probes, calipers, and inside gauges are used. It is necessary to use diagnostic instruments and devices, stands for determining defects and malfunctions, etc. Repair has different degrees of complexity. The degree of complexity is determined by the need to disassemble and replace the main assembly units and parts, including the housing, electric motor, etc. For example, the repair of household radio-electronic equipment is divided into:
Block method of repair associated with the disassembly and replacement of the main elements of the equipment: a kinescope, a scanning line and other elements;
Repair carried out without disassembly and replacement of the main assembly units.
Repair and maintenance of household appliances is provided by repair technologies that are regulated by regulatory documents (technological maps, specifications, standards, rules and regulations). The customer may refuse the repair in full. In this case, the service organization guarantees the customer the compliance of the device parameters with the requirements of the standard only to the extent of the repair performed. The receiver makes a note about this in the accompanying document for the repair.
Service companies do not accept devices and equipment for repair (including after the expiration of their service life), if the customer refuses to eliminate malfunctions, the presence of which leads to a violation of safety requirements. In the event that faults related to its safety are discovered during the repair process, the service company must inform the customer about this and re-issue the order, taking into account the additional amount of work.
If the customer refuses additional work, a note is made in the acceptance document that the device or apparatus is unsuitable for operation, confirmed by the signatures of the customer and the contractor.
After the repair, the technical control service of the service organization or persons entrusted with control functions carry out quality control of the repaired devices.
Repaired appliances must function in all modes provided for by the regulatory documentation for a new household appliance of a particular type, the deviation of performance indicators of repaired household appliances during their service life should be no more than 20% compared to new ones.
appliances.
After the end of the service life, the indicators can be set in agreement with the customer when receiving household appliances for repair. Repaired devices must comply with safety requirements. Decrease in the safety indicators of repaired household appliances (within the limits established by the manufacturer) during the service life and after its expiration is not allowed. Household radio-electronic equipment that has been repaired must be sealed. When the equipment is put into operation, the accompanying document issued to the customer is marked with a mark confirming the technical acceptance and safety of the equipment. When issuing repaired radio-electronic equipment, household machines and appliances, an employee of a service company inspects the equipment and demonstrates its operation. Turning on, turning off or switching household radio-electronic equipment, household machines and appliances should be easy, smooth, without delays and repeated switching on. Radio-electronic equipment powered by the electrical network must be checked for the required value of electrical insulation resistance. After the repair, the customer is issued an accompanying document describing the repair and the repaired device. Service companies providing repair and maintenance services provide guarantees that the repaired device meets the requirements of the standard. When accepting household appliances and machines from repair, the customer has the right to check the compliance of the work performed with the list of defects specified in the order. On the accompanying document issued to the customer when the device is put into operation, a mark is placed confirming the technical acceptance and safety of the device. For repaired household machines and appliances, warranty periods are established:
6 months - when performing repair work related to the first group of complexity;
12 months - when performing repair work related to the second group of complexity.
For devices discontinued more than 10 years ago, the production of spare parts for which has been discontinued, the warranty period is set at least 3 months. Warranty periods are established for repaired radio-electronic equipment
When carrying out repairs in a hospital: for color TVs, VCRs and equipment of the highest complexity group
At least 3 months, for the rest of the equipment - at least 4 months;
When carrying out repairs at the place of operation: for color TVs, video recorders and equipment of the highest complexity group - at least 1 month, for other equipment - at least 2 months.
For new components installed during the repair of household appliances and machines, the warranty period must correspond to the warranty period established by the manufacturer (seller). The warranty period is calculated from the date of acceptance of the work (provision of services) - the issuance of repaired household appliances or radio-electronic equipment to the customer and is considered valid if the customer observes the operating rules.
During the warranty period established by the service organization, repeated repairs of household appliances and radio electronic equipment are carried out at the expense of the service organization, except for the payment by the customer of the cost of assembly units and parts that were not replaced during the previous repair.
When performing repeated repairs within the warranty period established by the service organization, the last warranty period is extended for the period from the date of contacting the service organization until the date of acceptance of the work (rendering of the service) - the issuance of household appliances or radio-electronic equipment.
The customer, at his request, is provided with services for the transportation of repaired household machines and appliances. Transportation of household machines and appliances is carried out in a vertical position in a closed vehicle, which ensures the safety of appliances from mechanical damage and precipitation.
Storage of repaired and accepted for repair household appliances is carried out separately in a warehouse in dry rooms at a temperature of at least 5 ° C, without the presence of acid, alkali and other harmful substances in the atmosphere. The most convenient placement of devices on the racks. Storage conditions must exclude mechanical damage.
Jewelry repair ensures the restoration of the design and consumer properties of jewelry.
Services for the repair and manufacture of jewelry are provided to consumers at stores selling jewelry or in jewelry workshops. The direct executor of repair and manufacturing services is the master jeweler.
When repairing or making jewelry, measuring, cutting tools, tools for bending and straightening (pliers, vise), tools for soldering, polishing and grinding, seaming and crimping metal are used. Acceptance of products for repair is carried out by an inspector who has a specialized education as a master jeweler. Upon acceptance, he examines the product, determines the materials of manufacture, defects and draws up a contract (receipt, other document) for the performance of work, which describes the work (with a sketch signed by the consumer) and precious
stones indicating the shape, size, weight, color, defects.
In the case of acceptance for repair or manufacture of jewelry made of precious metals belonging to the consumer, the contractor shall determine the sample of precious metals on touchstones using reagents manufactured by state inspections of assay supervision.
Jewelry made from precious metals must comply with the samples established in accordance with the legislation of the Russian Federation, and be branded in the prescribed manner with the state assay mark by state inspections of assay supervision.
In the manufacture of jewelry from precious metals, the performer must have a personal name, the imprint of which is placed on the manufactured products. Furniture manufacturing and repair provides consumers with the opportunity to restore old, used furniture or purchase custom-made furniture products. In addition, furniture workshops offer services for the manufacture and repair of baguette frames and wooden cornices, shields and solutions.
current for masking heating devices, etc. Furniture in the process of use is subjected to mechanical and physico-chemical influences, which reduce the strength of the structure, causing the destruction of furniture elements (legs, legs, armrests), etc. Over time, dents appear on the front surfaces,
ly, bullying, flakes, facing, decorative elements, finishing coatings are destroyed. In addition, the aesthetic properties of furniture are subject to obsolescence.
Laboratory work No. 8 "Procedure for organizing service maintenance of electrical machines"
The purpose of the work: To study the procedure for organizing the maintenance of electrical machines.
Working process:
Service center -- an organization engaged in the provision of service support and maintenance of machinery, equipment and other products. The activities of service centers include pre-sales, warranty and after-sales repairs.
Servicing a car in a car dealership guarantees protection from unforeseen situations for the owner of the vehicle, as well as the implementation of certain measures to keep the car in working order. To exclude or at least prevent significant breakdowns, it is necessary to periodically contact the service center for diagnostics. As a result, the timely elimination of minor breakdowns and damage. Typically, car maintenance includes checking primary assemblies and assemblies, changing oil and antifreeze, and if problems are found, replacing brake pads, belts, and spark plugs.
One of the decisive factors in a consumer's choice of product is how much support the supplier promises after the sale of that product. This factor is especially important when buying electrical household appliances, appliances and electronics, building materials, cars, etc., that is, in those areas where a breakdown or factory defect means that the product cannot be used for its intended purpose or prevents it.
When buying a product, the warranty period for the product and its service life are established. During the warranty period, the buyer is entitled to free repair of the goods or (in special cases -- see below) to replace it. After the expiration of the warranty period, the repair of equipment is carried out at the expense of the consumer. After the expiration of the service life of the product, the manufacturer has the right to refuse the consumer to repair this product.
The activities of service centers are regulated at the legislative level, in accordance with the laws of the country in which the service is provided. According to the Law on Consumer Rights of the Russian Federation, information about the product must contain the warranty period of the product, if it is established.
“Consumer rights in case of defects in the product”:
The consumer, in the event that defects are found in the goods, if they have not been specified by the seller, at his choice, has the right to:
demand a replacement for a product of the same brand (the same model and (or) article);
demand a replacement for the same product of a different brand (model, article) with a corresponding recalculation of the purchase price;
demand a commensurate reduction in the purchase price;
demand immediate gratuitous elimination of product defects or reimbursement of expenses for their correction by the consumer or a third party;
refuse to fulfill the contract of sale and demand the return of the amount paid for the goods. At the request of the seller and at his expense, the consumer must return the goods with defects.
In this case, the consumer has the right to demand also full compensation for losses caused to him as a result of the sale of goods of inadequate quality. Losses are reimbursed within the time limits established by this Law to meet the relevant requirements of the consumer.
The new version of the Law mentions the period during which the consumer has the right to make a claim for the replacement of goods and for a refund if defects are found in the goods -- 15 days. If the color, size, shape of the product does not suit the consumer, then the product cannot be exchanged! After the expiration of the period established in 15 days, these requirements are subject to satisfaction in one of the following cases:
discovery of a significant defect of the goods;
violation of the deadlines established by this Law for the elimination of defects in goods;
if, in case of repeated failure, the customer was unable to use his product for more than 30 days due to being under repair
Household electrical appliances and machines use electricity differently. In one case, it turns into mechanical energy of the moving parts of electric motors (washing machines, vacuum cleaners, some refrigerators, kitchen machines, fans, etc.), in the other, it gives heat (electric heaters), in the third, it feeds radios and televisions. Installation issues, rules for the operation and maintenance of household electrical appliances are usually detailed in the instructions attached to them. Below will be given only additional recommendations for the repair and improvement of their work.
The electric motor is the main part of many electrical appliances. Depending on the purpose of the machine, engine designs are very diverse. In washing machines, refrigerators ("ZIL - Moscow", "Saratov"), players, fans, asynchronous electric motors are installed. In vacuum cleaners, sewing machine drives and other devices that require a high rotational speed, more complex commutator motors are used.
If the engine of an electrical appliance or machine does not work, first of all, you should check whether there is current in the home network. Then you need to inspect the plug, connecting cord, switch. After making sure that the current is supplied to the electric motor, look for the cause of the malfunction in the motor itself.
This may be a break in the wires in the winding, poor contact at the point of connection of the wires, and in the collector motor, in addition, wear of the brushes, wear or contamination of the collector. Sometimes the engine is bad, running due to overload. Therefore, if you do not find any obvious malfunctions in it during a superficial examination of the engine, you need to carefully check the mechanism that is set in motion. Overloading can be caused either by the work done by the mechanism or by the increased friction of its parts. Care must be taken to ensure that the mechanisms are always lubricated and installed without distortion, and that the drive belt is not too tight.
For example, the widespread SM-1.5 washing machine sometimes starts to make a lot of noise. This is usually due to the fact that the ribbed disk of the activator, during rotation, touches the inclined partition (bottom) of the machine. The activator shaft (Fig. 152) is connected to the electric motor by a belt, which, with strong tension and wear of the stuffing box, warps the disk. To eliminate the malfunction, the laundry extraction mechanism is removed inside, the machine is turned upside down, the nuts of the electric motor are loosened and the belt tension is adjusted by slightly shifting it.
In commutator motors, the most vulnerable spot is the commutator brushes, which quickly wear out and fail. In vacuum cleaners and electric polishers, the brushes should be inspected for the first time after 300-400 hours of operation after purchase, and thereafter every 150-200 hours of operation.
Brushes on commutator motors should move easily in the brush holders and have good contact with them. If this requirement is not met, there may not be good contact between the brushes and the commutator. And the quality of the contact is determined by the uniform wear of the working end of the brush. If it is erased only on one side, the contact is bad, the brush must be rearranged and rubbed. Uniform wear is ensured only if the brush is directly above the axis of the commutator. To grind the brush, wrap the sandpaper around the collector with the abrasive up and, pressing the brush against it, manually turn the anchor in one direction or the other (Fig. 153).
A perfectly serviceable collector has a smooth surface with a uniform yellow-brown tint. If the collector becomes rough and covered with dark spots with a black burn, it must be cleaned with fine glass sand and polished with a clean cloth. The skin is best strengthened on a wooden block. Sandpaper cannot be used in this case.
The accumulation of metal dust, abrasive particles and dirt on the insulation between the collector plates causes current leakage. It is convenient to clean the insulation with a pointed stick or a match (Fig. 153, B).
Excessive noise and vibration in small electric motors in household machines can occur for various reasons. Most often this is due to bearing wear or insufficient lubrication. If the armature axis wobbles in the bearings, this means that the gap between them is too large, the bearings should be replaced, otherwise the armature may touch the stator winding. A rattling noise when starting the motor is a sure sign of bearing wear.
The vibration of the engine (and with it the entire machine) is often caused by an unbalanced rotor. It is very difficult to eliminate this defect at home, besides, balancing requires accurate calculation and great skill. Therefore, the vibrating motor should be taken to a specialist workshop for repair.
In vacuum cleaners, the cause of noise is often the loosening of the fan mounts, the blades of which, during rotation, touch the walls of the casing. The device must be disassembled and the nuts tightened. If that doesn't help, check for bent fan shaft and, if so, correct the deflection with light hammer blows through the wood spacer.
In an electric kettle, iron, boiler, stove and any other heating device, the main part is a spiral of conductor with high resistance - a heating element (Fig. 154).
Heating elements are made of nichrome, fechral, constantan and some other alloys.
The most widely used nichrome and fechral. They withstand temperatures up to 800°C, oxidize little and work reliably for a long time.
During the operation of the heating device, a current passes through the spiral, so it is carefully isolated from other metal parts of the device. It is clear that insulating materials must be sufficiently strong and heat resistant. Fireclay, mica, asbestos, micanite, porcelain have such properties.
Ceramic tile bases, cones of reverberatory stoves, rods of electric fireplaces can withstand temperatures up to 1400 ° C and are usually made of fireclay. In electric irons, kettles and pans, a resistance spiral is often wound on a micanite base (Fig. 154, B), which can withstand temperatures up to 600 ° C. Stronger heating can cause micanite cracking, which is sometimes observed during repairs.
Porcelain is used to make insulating beads, which are put on the spirals at the place where they are connected to the clamping terminals.
To direct and reflect heat (so that, say, the lower part of the iron is heated, and not the lid), electric heaters use gaskets made of heat-insulating materials, most often asbestos.
Household electric heaters usually operate for 600-1000 hours without repair. With careless handling and poor care, the device deteriorates, of course, earlier than this period.
If the device does not work when turned on, you must first check whether there is current in the network, whether the plug is working, and whether the connecting cord is broken. To check the connecting cord, it is enough to use it to turn on a working electrical appliance, such as a lamp. After making sure that there is current in the network, the plug socket and the connecting cord are in order, you need to look for a malfunction in the device itself.
The heating element of the electric tile is a spiral of fechral or nichrome wire, which fits into the grooves of the ceramic base (Fig. 155, A). Tiles are also produced with a heating element covered with a deaf metal casing (Fig. 155, B).
The ends of the spiral are passed inside the metal body of the tile through a ceramic disc and fastened with nuts to the contact pins. Porcelain beads are put on the ends so that they do not short-circuit. The contact pins are insulated from the metal body of the tile with porcelain cups (in some designs, with mica). The ceramic base is fixed in the body of the tile with a metal ring or frame, which is put on from above. In some designs, the frame is screwed to the body.
Most often, the tile fails due to poor contact between the helix and the contact pins, since during shocks the circuit in this place periodically opens, sparking occurs, and eventually the contacts burn out.
To eliminate the malfunction, it is necessary to remove the clamping ring of the tile, carefully lift the ceramic base and seal the fastening of the spiral to the pin. To fix a burnt contact, the end of the spiral is cleaned to a shine, twisted into a ring with one or two turns (Fig. 156, A), put on the contact pin and firmly clamped with a nut between two washers (Fig. 156, B).
The contact pins are often burned on the outside, from the connection side of the cord block. These pins do not make good contact and should be replaced with new ones. The most common way to mount them in the instrument case is shown in the figure.
The place where the spiral burned out is easy to detect during external examination. The ends of the burnt-out spiral must be cleaned and twisted tightly, and then the junction should be wrapped with a thin brass or tin strip and squeezed with pliers (Fig. 157, A), otherwise the spiral will burn out again in this place. It must be borne in mind that after each such repair, the spiral becomes shorter, so it heats up more and burns out faster. After two or three repairs, it is better to replace it with a new one, designed for the same voltage and power. On the body of the tile and on the spare coil, these parameters are indicated.
When installing a new spiral in a ceramic base, they often make a mistake - they stretch it unevenly. Closely spaced coils from the mutual thermal effect heat up more strongly, and in this place the coil can quickly burn out. The stretching step, i.e. the distance between adjacent turns, must be at least three times the diameter of the wire. In order for the spiral to have a uniform pitch, it must first be stretched to the total length of the groove of the ceramic base, which can be measured with a thread. After laying the spiral, its ends are isolated with porcelain beads and firmly pressed with nuts to the pins.
With careless handling, shock, shaking, the ceramic base of the tile may crack. If it is not possible to replace it with a new one, they resort to tightening with a hoop or wire. The hoop is made of tin (Fig. 157, B). In order for it to tightly tighten the cracked base of the tile, the hoop needs to be heated a little and put on cold ceramics.
The base can also be pulled together with wire. However, both methods of restoration are not reliable, so at the first opportunity you need to purchase new ceramics.
Electrical appliances with a hidden heating element, as a rule, are more complicated than tiles, so during the repair process, you need to remember well the order of disassembly and the attachment points of individual parts.
To check the health of any electrical device and the correctness of its assembly, you can use the previously mentioned control light. If the lamp connected in series from one socket of the socket through a wire to the heating element of the device does not light up (Fig. 158, A), then the circuit in the device is open or the heating element has burned out.
In case of incorrect and careless assembly, the current-carrying parts of the device can be connected to the case. In this case, the light bulb, turned on, as indicated, will burn if one of its wires touches the body (Fig. 158, B). Such a device cannot be used without eliminating the malfunction.
During ironing, the working surface of an electric iron gives off part of the heat to the object being ironed. If the iron is turned on, but it does not work, it overheats. Therefore, the iron, heated to the desired temperature, must not be left unused for more than 10 minutes. When overheated, the insulating material (micanite) in the flat heating elements crumbles, and the lead plates with which it is attached to the contact pins burn out. If a spiral is used as a heating element in an iron, it most often burns out at the contact pins.
To disassemble the iron and replace or repair the heating element, use a wrench or pliers to unscrew the two nuts on top of the body and remove the handle and cover (Fig. 159, A). In some irons, the socket with contact pins is attached to the cover, therefore, by lifting it, you must first disconnect the output ends of the heating element. Then, the nuts holding the heat-insulating material, the load, the electrically insulating plates and the heating element are unscrewed - a micanite plate with a wound fechral or nichrome tape or a spiral with strung porcelain beads (Fig. 159, B). For flat heating elements, only brass plates are often burned, with the help of which they are connected to the contact pins. They are easy to replace with new ones. If the nichrome tape is burned out at the point of attachment to the brass plates, it is necessary to clean the burnt end of the tape and firmly clamp it with pliers with the end of the plate bent 180 °.
Electric kettles, coffee pots, pots are arranged in much the same way as the kettle shown in Figure 160, and their repair is not difficult.
O.A.Grigorieva
TYPICAL TECHNOLOGICAL PROCESSES FOR MAINTENANCE OF HOUSEHOLD MACHINES AND APPLIANCES
Guidelines
Anzhero-Sudzhensk
2014
UDC 621.3
BBC 31.2
Minutes No. 1 dated 10.09.2014
Grigoryeva O.A., Lecturer, GBOU SPO Anzhero - Sudzhensky Mining College
Reviewers:
Gergal I.N., Candidate of Technical Sciences, Director of the Anzhero-Sudzhensk Mining College
Sidartsov S.M., head of the signaling and communication section of the Anzhero-Sudzhensk vocational school
The guidelines present practical work for students enrolled in the training program for mid-level specialists, specialty 13.02.11 "Technical operation and maintenance of electrical and electromechanical equipment (by industry)". The texts of practical works contain the necessary theoretical information about the designs of household machines and appliances, helping students to systematize knowledge for the development of professional competencies related to the performance of service maintenance of household machines and appliances. Guidelines for the implementation of practical work have a strict logical sequence of the order in which the task is completed and the report is compiled. Compiled to help teachers and students to organize practical training on MDK 02.01 "Typical technological processes for servicing household machines and appliances."
CONTENT
| Introduction | 4 |
| Practical work No. 1 - Determining the characteristics and malfunctions of thermal household appliances | |
| Practice #2 - Repairing hair dryers, steam irons and fans | |
| Practical work No. 3 - Diagnostics and troubleshooting of electric meat grinders | |
| Practical work No. 4 - Repair of electric kettles | 19 |
| Practical work No. 5 - Repair of blenders, hand and table mixers | |
| Practical work No. 6 - Repair of an electric kettle-thermos (thermopot) | |
| Practical work No. 7 - Repair of automatic washing machines | 38 |
| Practical work No. 8 - The technological process of disassembling the components and assemblies of the washing machine | |
| Practical work No. 9 - Operation and arrangement of the Biryusa-2 compression refrigerator | |
| Practical work No. 10 - Repair of household compression and absorption refrigerators | |
| Practical work No. 11 - Malfunctions of microwave ovens and methods for their elimination | |
| Practical work No. 12 - Typical malfunctions of vacuum cleaners and methods for their elimination | |
| Practical work No. 13 - Typical malfunctions of air conditioning systems and methods for their elimination | |
| Practical work No. 14 - Typical malfunctions of kitchen hoods and methods for their elimination | |
| References and Internet sources | 101 |
Introduction
There is always a lot of homework in every house and, unfortunately, it takes us a lot of time. But, fortunately, mankind has come up with many useful devices, household appliances that allow mechanizing labor-intensive work at home: cooking food, washing and ironing linen, cleaning clothes, cleaning rooms, etc. with the least labor costs. Household appliances save our time and create home comfort, facilitate working and living conditions.
But, sadly, during operation, these irreplaceable helpers lose their efficiency, mainly due to wear and tear of individual parts. Then it's time for us to take care of our friends.
Of course, the easiest way out is to throw away old household appliances and purchase new ones, but after all, it has faithfully served us for many years and has far from exhausted its resource. Or simply we are so accustomed to this or that technique that we don’t want to part with it. For this, there are services for the repair and maintenance of household appliances.
Public service plays a very important role. It actively contributes to the convergence of the living conditions of the urban and rural population, the retention of personnel, especially in the countryside and in populated areas, and the rational use of material and labor resources.
One of the promising and rapidly developing industry groups of household services is the repair of household machines and appliances. Technological progress has a great influence on the development and improvement of the industry group of services for the repair of household appliances. Any machine that is in use requires constant maintenance (lubrication, cleaning, elimination of minor malfunctions) and periodic repairs (replacement of failed parts, assemblies and assemblies). Thus, household appliances that are in the operation of the population, its constant structural complication, contributes to the rapid development of an industry group for the repair of household appliances.
Household appliance repair enterprises provide the population with a large number of services, such as: repair of refrigerators, washing machines, vacuum cleaners, floor polishers, sewing machines, electric shavers, etc. These enterprises must constantly improve their activities. Complete satisfaction of the population in household services, improving the quality and improving the culture of service, reducing the time for fulfilling orders - these are the main directions for improving the activities of enterprises for the repair of household appliances. The successful solution of all these tasks largely depends on the level of organization and planning of their activities.
In order to improve the quality of service, as well as expand the number of services to the population, enterprises are introducing new types and forms of service, such as:
repair in the presence of the customer;
taking orders by phone;
repair today for today;
use of the exchange fund of household appliances.
These classes allow you to consolidate theoretical knowledge and develop certain skills in the repair of household appliances in the course of these practical works.
In accordance with the Work Program, students perform 15 practical work. Before starting, you need to familiarize yourself with the safety precautions. (see annex 1)
Tasks are performed by students in microgroups. Practical work is carried out on A4 sheets in the prescribed manner (Appendix 2 and 3). All entries must be accurate.
Completed practical work is viewed by the teacher. The defense of practical work is carried out at the end of the lesson or during the second subgroup on time.
Delivery and defense of practical work after the deadline is allowed only for a good reason with the permission of the teacher.
Criteria for evaluating the results of practical work:
| Percentage of effectiveness (correct answers) | Assessment of the level of training |
||
| Point (mark) | verbal counterpart | criteria for evaluation |
|
| 90÷100 | 5 | Great | implementation of schemes according to GOST; accurate performance of work; conclusion on the performance of work; correct answers to control questions |
| 80÷89 | 4 | well | timely delivery of work (at the end of the lesson); implementation of schemes according to GOST; correct disassembly and assembly of the layout; accurate performance of work; conclusion on the performance of work; incorrect answers to control questions |
| 70÷79 | 3 | satisfactorily | timely delivery of work (on time); implementation of schemes according to GOST; correct disassembly and assembly of the layout; conclusion on the performance of work; no answers to security questions (or wrong ones) |
| less than 70 | 2 | Unsatisfactory | late delivery of work (on time); non-fulfillment of schemes according to GOST; incorrect disassembly and assembly of the layout; inaccurate performance of work; there is no conclusion on the performance of the work; no answers to security questions |
Practical work No. 1
Determining the characteristics and faults of thermal
household appliances
Objective
1. Calculate electric heating equipment (OK 6)
2. Predict failures, determine resources, detect defects in electrical household appliances (PC 2.3)
Devices and materials
Thermal household appliance (kettle, electric stove, boiler, etc.)
Fig.1 Electric heating equipment
Explanation for work
Repeat the theoretical material on electrical engineering (Work and power of electric current. Thermal effect of current Ohm's law for a circuit section)
Class equipment
Operating instructions for electrical heating equipment
Theoretical information
Malfunctions of electric heaters and methods for their elimination
The following malfunctions are most common: heating and burning of contacts; violation of insulation between electrically conductive parts, the case and other parts of the device that are not energized; conductor breakage and damage to the insulation of the power cord; cracks in ceramic parts; burnout of heating coils, heating elements, power switches, lighting equipment, etc. Very often in household appliances, the formation of conductive bridges is observed at closely spaced electrical circuit contacts. This phenomenon is called tracking. This happens when they appear on the surface of the electrical insulating material of electrolytic pollution and the impact of electrical voltage. When tracking occurs on the surface of the assembly with electrical contacts, a short circuit occurs between the conductive cores. To eliminate the malfunction, it is necessary to carefully clean this place until the burnt material is completely removed and check the maximum voltage.
Malfunctions in electric heaters occur from increased heating due to significant resistance and sparking of contacts. To eliminate this malfunction, it is necessary to clean the contact surfaces to a shine with a knife or sandpaper and achieve a snug fit of one contact surface to another. In bolted connections, this is achieved by tightening the nuts on the bolts, in plug-in connections, by expanding the slots of the plug. If the pins are not cut, then contact can be improved by reducing the diameter of the contact sockets of the socket. To do this, disconnect the socket from the mains, unscrew the fuse plug, remove the cover of the socket and carefully reduce the diameter of the socket using pliers. Before testing the quality of the contact, it is recommended to close the socket cover, and then put the fuse plug in its place. After repair, the connection must be tight and motionless. This will ensure good contact and eliminate increased heating of the connecting parts.
Burning of contacts occurs due to sparking. Burnt contact parts, pins, contact sleeves, etc. needs to be replaced.
The destruction of the conductors and insulation of the power cord is often caused by strong heat, the action of substances that corrode the insulation, frequent twisting and unwinding.
If only the insulation is damaged in the cord, then the damaged area must be insulated with insulating tape. From above, the insulation should be wrapped with threads in the color of the cord.
If the conductors of the cord are broken, you must first find the place of damage. To do this, it is necessary to turn on a portable electric light bulb in series with the cord. After connection, the cord must be bent in places of possible breakage, mainly near the terminal block and plug. If at the same time the light starts flashing, this indicates that the conductors are damaged at the bend. This work can be done with a combined instrument or by other means.
To eliminate the malfunction, the cord must be disconnected from the mains, the damaged part of the cord must be cut out, and the serviceable ends connected. Shortening the cord is not allowed.
The quality of repair of electric heaters is established in the following sequence:
visual inspection;
insulation resistance test;
insulation dielectric strength test;
function check;
power consumption check;
checking the horizontal installation of burners (for electric stoves).