Failure electrical machinery and apparatus
Modern household appliances every year it becomes more difficult because of the desire of industry to make cars more affective and PRSPs “to improve the usability of their operation and increase durability. This does not mean that the appliances become less reliable. Now produced an iron f thermostat and humidifier consists of more than fifty details, but it is much more secure than the old irons, because the thermostat is in addition to compelling features to the consumer is also significantly extends the life of a spiral, periodically shutting her in the process.
The service life of household appliances is directly dependent on the timely care and compliance with the rules of operation set forth in the manufacturer’s instructions. In this first ‘part, efforts should be directed home worker. Complete repair of electrical household appliances can be made only at the domestic service, where there are special stands and other equipment. To identify and eliminate more or less serious faults household appliances in the home are necessary instrumentation.
Faults, which account for the majority of cases, the output of electrical machinery failure can be identified and addressed in a control light and continuity tester circuit. The simplest tester is a battery from a flashlight bulb with a power-on sequence, In another embodiment, the power supply using an electric network and the neon light (eg, MLT-90) for display. Light bulb can be easily integrated into an ordinary plug, which in its cap, the diameter of the lamp, you need to drill a hole. As the resistance of the resistor type used MLT-1 at 100 k. When the contacts are closed probe device also can be used as a night light.
Getting to repair any household electrical machine, we must first study the instructions of the manufacturer for its operation, a good understanding of themselves and the principle of the scheme to have the electrical part. Fasteners (nuts, bolts) of the modern household appliances are often closed plastic . In the process of dismantling try to sketch on paper, the mutual arrangement of parts, wiring code and place of their accession. This will greatly facilitate the follow-up work, and most importantly – to ensure correct assembly.
Plug the power cord and the supply of devices, especially portable (irons, electric shavers, irons, electric drills, kettles, etc.) are the most common cause of the problem and, by the way, is most easily avoidable. Frequent bending at the entrance to the unit or at the plug wires under the insulating sheath cable break off. Sometimes a break is detected in the ground probing cord kinks. In the plug may be poor contact with the pins. Disassemble the plug, inspect the pins, tighten the screws fixing the wires. Provided that the power outlet is working (its faults we talked about earlier), it should be thoroughly checked the supply cord. Remove the cover where the wire enters the device, locate the wire connecting terminals, insert the plug into the socket and tap terminal ends of the control light. If the lamp does not light up: – a break in the cord if the lights – a fault in the device.
For the final test cord, disconnect it from the device, connect one pin plug with a wire tester, another wire tap the opposite ends of the cord. At one of these circuit tester should be closed. If you become isolated, connect the cable tester with a different pin plugs and check the second wire cord. While checking the wires try to bend them in different directions, as the contact may be impaired in the bends.
In the household electrical appliances, electricity is used differently. In one case, it is converted to mechanical energy of the moving parts of electric motors (washing machines, vacuum cleaners, some refrigerators, kitchen appliances, fans, etc.), in the other, gives heat (electric heaters), the third-feeds radios and televisions. Therefore, further testing of the non-working device depends on the principle of its operation.
Motor bulk of many household machines and devices. 8 depending on the destination machine engine designs are very diverse. In washing machines, refrigerators, DVD players, fans, mounted induction motors. Vacuum cleaners, coffee grinders, electric drills, saws and other machines that require high speeds are used somewhat more sophisticated collector motors.
Seeing as described above, that the current supplied to the motor, and the machine is not working, the reason should be sought in the motor itself. This can be broken wires in the winding in a poor contact connection wires and commutator motor, in addition, brush wear, deterioration or contamination of the collector.
Sometimes the engine does not work due to overload. Therefore, not finding a cursory inspection of the engine is apparently wrong, you need to carefully check the mechanism that is driven. Overload can be caused either by the work of the actuator, or increased friction of its parts. Overload at work very often burn out the motor windings, which is detected by the characteristic smell of burning insulation. Make sure that the arrangements were always greased and installed without distortions, and the drive belt is not too taut.
In the collector engines most vulnerable spot – collecting brushes which wear out quickly. Periodically inspect brushes commutator motor. Pulling them out of the slot, label which side is set in place. Remove dirt with a brush holders gasoline or acetone. Brushes should move freely in the holders. When caused by more than half the initial height, brushes need to be replaced. As the wear on the brush pressure springs is reduced and they can be pressed tightly to the surface of the collector. Change to both brush and be sure to grind them. To do this, wrap around the manifold grit sandpaper up and pressing her brush manually turn anchored in one direction and then the other.
Quite serviceable manifold has a smooth surface with a uniform yellow-brown tint. If the collector becomes rough and covered with dark spots with black podgarom, it is necessary to clean the glass to fine sandpaper and polish with a clean cloth. Sandpaper is best to strengthen the wooden bar. Use sandpaper in this case impossible. The accumulation of metal dust particles of grit and dirt on the insulation between the collector plates causes leakage current. Insulation is easy to clean sharpened stick or a match. When brushes are working normally in contact with the collector of visible blue uniform arcing. Excessive sparking yellowish with a simultaneous loss of engine power means bad contact brushes.
Excessive noise and vibration of small household electric cars can occur for various reasons. Most often this is due to bearing wear or lack of lubrication. If armature reeling axle in bearings means that between the gap is too large, the bearings should be replaced, or the anchor may touch the stator winding. A rattling noise when the motor starting – a sure sign of bearing wear.
Increased refrigerator noise during operation, a marked swing of the cabinet when the engine is switched off and is often due to the fact that the compressor casing slack on hangers and touches the frame. The fault is corrected adjustable spring tension suspension.
Vacuum cleaners are often the cause of the noise attenuation fixtures fan whose blades during rotation hurt the housing wall. The device is necessary to disassemble and tighten the nut. If that does not work, check to see if the fan shaft bent, and, if it happens, eliminate the deflection light hammer blows through the wooden lining.
When lubricating motor bearings should be used lubricants recommended by the factory – manufacturer of home machines. If there are none, it is necessary to lubricate close substitute, guided by considerations of lubricant viscosity (see “on lubricants). Avoid excessive lubrication. The oil can get to the brushes and commutator, cementing, close the armature winding. As the lubricant expands when heated, do not tamp it into the bearings for more than half the cage.
The main mouth of electric heaters is the spiral of wire with a high resistance – heating element. They can withstand temperatures up to 800 ° C, and little oxidized operate reliably for a long time, typically 600-1000 Outdoor CV performance. Being placed in a closed metal housing, heating elements operate up to 5,000 hours widespread in closed tubular heating elements have electric heaters (heating elements). They represent a metal tube, inside which the heating coil is pressed into the filler. Heating elements are now the main honor the heating elements of electric irons, cookers, kettles, etc.
During the period of the spiral heating unit is energized, so it carefully isolated from other metal parts of the device. It is understood that the insulating materials should be sufficiently durable and heat resistant. These properties are fire clay, mica, asbestos, mica, porcelain.
Ceramic tiles, cones, reverberatory furnaces, electric fireplaces rods can withstand temperatures up to 1400 ° C, and produced, as a rule. Insulation made of porcelain beads, which put on a spiral in connecting them to the screw terminals. To direct and reflected heat (heated to, say, “bottoms iron, not cover) used in electrical heating appliances laying of insulation materials, most often from asbestos.
To regulate the temperature of electric heating appliances and thermostats set temperature limiters. The difference between them is that the heating temperature limiter which limits the temperature of the appliance by automatically opening the circuit (for example, electric heater), whereas the thermostat is automatically maintained within certain temperature (for example, refrigerator, iron).
The most common element is a bimetallic temperature control plate. When the thermostat contacts are closed, current flows through the heating element of the device, for example, iron, heats it and record. When heated bimetallic plate bends and breaks the circuit. Iron cools off again until the record does not close the circuit. The cycle repeats itself, and the iron temperature is stabilized at a level which depends on the cycle time.
By changing the position of the second contact temperature controller, you can change the time of the cycle (opening – closing contacts), and hence the degree of heating of the soleplate. As mentioned earlier, the electric heaters are designed for long service life, but the negligence and poor care faults occur earlier.
All modern irons are available with temperature controllers, and some models – from the steam humidifier and sprinklers. Many models are equipped with indicator lights. As the heating element used in most cases heating elements, but are also elements of nichrome helices.
Conducted when the device does not work, as mentioned earlier, you need to check current availability on the network socket and plug, and the connection cord. Due to the fact that in many heating devices I interchangeable detachable cord to test enough to include it with the help of efficient electrical appliances. Making sure that the cord is in order, check the thermostat. This is a fairly reliable instrument and rarely require adjustment. With a large discrepancy specified operating conditions can be adjusted only in the workshop, which includes a special stand. At home, check the connections and the condition of the contacts on the plates. Scorched contacts need to clean up a piece of fine sandpaper. If the regulator is rusted screw axis, the machine will drop of oil. Do not spill oil on the contact plates and avoid touching them with your fingers.
Further circuit continuity tester, check the heating element. To do this, the ends of the wire tester, connect the wires to the terminals of skin, then remove one wire from the plug and connect to the case of iron. While in the first case, the chain is not closed (burned spiral), and the second is closed (there is a short to ground), the heater should be replaced. Do not attempt to connect the ends of the coil burnt-open items: being shortened and poorly connected, it will burn out soon anyway.
The heating element of modern electro usually in a hermetically sealed box. This tiles closed. They are durable , safe to use, with a uniform heating of the surface , but have a significant disadvantage because of the large heat capacity they are heated for a long time (15-20 min) and require that the base of the pan was thick and tight to the surface of the heating element.
Superior in this regard to the tiling tubular heating element. These shawl heat is negligible, and they heat up for 2-3 minutes. Plates are closed element , typically a few degrees heating is achieved by incorporating different combinations of the two helices of one heating element. Spirals be included separately, sequentially , in parallel with the corresponding change in power .
Continue to produce and traditional tiles with an open heating element. The main fault with tile sheathed heating element – the element is blown . It can not be repaired and must be replaced. Heating elements of this type are usually fastened with screws to the base tile . To disassemble , remove the bottom cover tiles, loose wires on the switch n unscrew the screw element. Before you disconnect the wires , label them on the heating element and with which they are connected to the terminals on the switch. The fact that the wiring terminals on the heating element does not labeled and determine their relative positions .
Another fault of tiles with a private member – it is scorching the switch contacts . Contacts can be smoothed out with the tip of a sharp knife , flat needle files or sandpaper .
In the tile with an open heating element inside the ends of the coil are passed through a metal body ceramic tile diene and nuts are attached to the contact pins . The ends are not short- circuited , they put on porcelain beads. The contact pins are isolated from the metal body porcelain tiles cups ( in some designs of mica ) . Ceramic tile is secured in the housing metal ring or frame , which fit reconciliation . In some designs, the housing is screwed to the frame .
Most tile fails due to poor contact with the coil contact pins , since it pushes the chain in place periodically opened, sparking occurs , and eventually contacts burn. To correct, it is necessary to remove the compression ring tiles, carefully remove the ceramic base and seal the mounting spiral of the pin . To fix a blown contact, the end of the stripped sanded to perfection , rolled up in the ring with one or two turns , put on the contact pin and nut firmly clamped between the two washers.
The contact pins are often burn and outside of the connecting pads cord . These pins do not provide good contact and should be replaced. The most common method of fastening them to the fixture shown in .
The place where the spiral is burned , it is easy to detect by external examination . The ends of the spiral must clean up the burned-out and tightly twisted together , and then the connection to wrap a thin strip of brass or tin and squeeze the pliers , or a spiral in this place again blows . It should be borne in mind that after each repair helix becomes shorter , so it is very hot and will burn faster . After two or three fixes it better to replace the new , rated for the same voltage and capacity . On the case of tiles and a spare spiral , these parameters are specified .
Installing a new spiral in the ceramic base , often make the mistake I ” uneven stretch it. The closely spaced windings of the mutual thermal influence hotter and this site helix can burn quickly . Step stretching, ie, the distance between adjacent coils must be at least tripled the wire diameter . The coil had a uniform step , it must be pre- stretch for the total length of the groove ceramic base, which can be measured by a thread. After laying the ends spiral isolated porcelain beads and nuts firmly pressed to the pins .
Rough handling , shock , concussion Ceramic tile can crack . If you can not replace it with a new , resort to the contraction of the hoop or wire. The hoop is made of tin. So he pulled together tightly cracked tile base , you can wrap and put a little heat on the cold ceramic.
After getting acquainted with the repair of electric motors and heaters detection and fault in the heating devices with fans ( hair dryers, electric fireplaces , etc.) represent special difficulties will not.