Automatic switches types and purpose. Types of automatic transmissions

Drivers of cars equipped with a manual gearbox, from time to time, in order to engage the desired gear, have to control the car using only one hand. In contrast, happy owners of vehicles with an automatic gearbox can hold the steering wheel with both hands throughout the entire movement. And now we will look at the basic types of automatic transmissions.

Summary :

Types of automatic transmission | Types of automatic transmissions

Classic hydraulic “Automatic” (automatic transmission) | Hydraulic automatic

A striking example of a classic automatic transmission is precisely hydraulic type automatic transmission, aka hydraulic automatic machine. The absence of a direct connection between the engine and the wheels is the peculiarity of of this type automatic transmission The question arises: how is torque transmitted? The answer is simple - two turbines and working fluid. As a result of the further “evolution” of this type of “automatic machine”, the role of control in them was taken over by specialized electronic devices, which made it possible to add special “winter” and “sport” modes to such automatic transmissions, a program for economical driving and the ability to change gears “manually” appeared.

Unlike a manual gearbox, a hydraulic “automatic” requires slightly more fuel and takes longer to accelerate. But this is the price you have to pay for comfort. And it was “hydraulics”, challenging “mechanics”, that won a landslide victory in many countries, except for “old Europe”.

How does an automatic transmission work?

For a long time, drivers in Europe have all types of automatic transmission was categorically not accepted. Engineers had to do a lot before finally adapting the automatic gearbox for Europe. But all this ultimately served to increase efficiency and the emergence of such modes as “winter” and “sport”. In addition, the box learned to adapt individually to the driver’s driving style, and it became possible to manually change gears with an automatic transmission - which was important for European drivers.

Each manufacturer preferred to call such transmissions in its own way, but the very first name to appear was - Autostick. One of the most widespread inventions today is considered to be the invention of the AUDI company - Tiptronic. BMW, for example, called such a transmission - Steptronic, Volvo considered it a suitable name for the automatic transmission Geartronic.

However, even though the driver engages the gears himself, he is not considered to be completely manual. This is more semi-automatic, because the transmission computer continues to control the operation of the car regardless of the selected mode.

Robotic gearbox | Automatic robot

MTA (Manual Transmission Automatically Shifted) - or so-called popularly, is structurally, perhaps, in many ways similar to “mechanics”, but from a control point of view, it is nothing more than an automatic transmission. And although fuel consumption here is more moderate than with the same manual transmission, there are also some nuances. The “robot” is very effective only at a very moderate driving pace.

The more aggressive your driving becomes, the more painful the gear changes feel. Sometimes when switching, it may even seem as if someone is pushing you into the rear bumper. That is difference between a robot (DSG) and an automatic machine lies in the principle of operation of the first. However, the low cost and low weight of the automatic transmission completely compensate for this disadvantage.

About the DSG box Video

Why does the Robot need two clutches?

Volkswagen Golf R32 DSG with 2 clutches

Existing shortcomings seriously complicated operation, with a particularly acute impact on driving comfort. Therefore, during a lengthy “search”, the designers eventually came to a solution that solved the problems - they equipped the “robot” with two clutches.

In 2003, Volkswagen launched a robotic transmission with two clutches into mass production, installing it for the first time on the Golf R32. The name was given to him DSG(Direct Shift Gearbox). Here, even gears were controlled by one clutch disc, and odd gears by a second. This significantly softened the operation of the box, but another serious drawback appeared - the price of this automatic transmission is quite high. Although mass acceptance of such a transmission by car enthusiasts can solve this problem.

CVT | CVT gearbox

CVT transmission (Continuously Variable Transmission) - it changes torque smoothly, this is its feature. This type of automatic transmission does not have steps; its gears do not have a fixed gear ratio. And if we compare it with “hydraulics”, then we can monitor the work of the latter using the tachometer readings, but variator very measuredly picks up the moments of gear shifting while the speed balance remains unchanged.

CVT | Continuously variable transmission

Useful video about what a CVT transmission is

Features | Differences between a CVT and an automatic transmission.

Those drivers who are accustomed to “listening” to their car will not be able to love such a box, because, like a trolleybus, it does not change the tone of the engine. But it’s probably not worth abandoning the CVT for this reason. Engineers found a way out of this situation by adding a mode where “virtual gears” can be selected manually. The gearshift mode is simulated, allowing the driver to experience driving like a conventional automatic gearbox.

How to determine which gearbox is installed in a car, CVT or hydraulic automatic:

If possible, study technical documentation car. In most cases, the automatic is designated as AT (Automatic Transmission), the variator is designated CVT;
Look for information on the Internet. Usually in technical specifications You will definitely find the answer on popular sites;
Test drive. If the car is equipped with a variator, then you will not feel any, even subtle jolts or jerks; acceleration is similar to the acceleration of a “trolleybus”. On a classic automatic transmission you can feel the gear changes, although on a working one they are almost invisible, it is impossible not to “feel” them.

What is more reliable and better: a CVT, a robot or an automatic?

At the same time, for a long time, automatic transmission was installed on cars of the middle class and premium segment, but later the unit became widespread.

Due to its enormous popularity, as well as the constant tightening of regulations and standards regarding fuel efficiency and environmental friendliness, manufacturers are constantly improving automatic transmissions, offering innovative solutions, etc.

As a result, today we can distinguish at least three main types of “automatic machines”, which differ greatly from each other in design and operating principles, but each of them is called an automatic transmission. Next we will talk about what types of automatic transmissions there are, as well as what features this or that unit has.

If we talk about the advantages, the hydraulic automatic has a fairly long service life (in some cases up to 500 thousand km), and also provides a good level of driving comfort.

As for the main disadvantages, such a gearbox is expensive to repair, requires regular maintenance, is demanding on the quality of gear oil, is susceptible to prolonged loads and difficult operating conditions, and is not highly economical. We also note that losses in gas turbine engines lead to the fact that the efficiency of hydromechanical automatic machines decreases compared to analogues. As a result, acceleration dynamics suffer.

(variable transmission CVT) is a separate type of automatic transmission, which for a number of reasons is not as widespread as a hydromechanical automatic transmission.

This transmission, like an automatic transmission, has a torque converter to transmit torque from the internal combustion engine, but the box itself is very different. In short, there are two pulleys mounted on the variator shafts. These pulleys are connected to each other by a belt or chain. Depending on the load and speed, the driving and driven pulleys change their diameter, as a result of which the torque on the wheels also changes. And this happens extremely smoothly.

Taking into account the fact that there are no usual fixed speeds (steps), thanks to this feature, the CVT gearbox is called a continuously variable transmission (flexible change in gear ratio). This type of automatic transmission differs from its analogues in its maximum smoothness, since there is virtually no gear change. Engine speed is also kept at the same level, without a sharp increase or decrease.

As in the case of automatic transmissions, additional modes can be implemented (winter, economical, sports, as well as Tiptronic with imitation of manual gear shifting). When driving a car with a CVT, drivers note the complete absence of noticeable shocks, vibrations, etc. It is also worth highlighting good acceleration dynamics and fuel efficiency.

However, there are also disadvantages. First of all, it does not have a long service life, is extremely complex and expensive to repair, and is demanding on the quality and level of oil. This means that such a box is not installed in conjunction with powerful engines; it is highly not recommended to load the transmission during operation.

(robot box or robot automatic transmission) is another type of automatic transmission, which, for a number of reasons, became truly widespread about 20 years ago.

It is noteworthy that this unit was developed a long time ago and is actually a manual gearbox with one clutch, in which the operation of the clutch is automated, as well as the selection and on/off of the desired gear.

In simple words, Automatic transmission robot is automated (robotic) mechanics. Such a gearbox is characterized by low production costs (which significantly reduces the cost of the entire car), allows for significant fuel savings (similar to mechanics), as well as dynamic acceleration.

If we consider the disadvantages, then, first of all, we should highlight a noticeable decrease in comfort compared to automatic transmissions and CVTs. In simple words, the clutch remains exactly the same as on a manual transmission, but the robot does not always select the desired gear in a timely manner, quickly and accurately, cannot operate the clutch smoothly, etc.

As a result, at the moment of switching, shocks, jerks, etc. are felt, the robot delays gear changes and does not always accurately select gears in accordance with the constantly changing conditions while driving.

Also, actuators (servomechanisms, actuators) on robotic manual transmissions quickly fail, high-quality repairs are often impossible, that is, complete replacement. It is important to understand that such mechanisms are quite expensive.

(for example, DSG or Powershift) can be considered a more technologically advanced and advanced version of a conventional box - a robot. At the same time, units of this type are devoid of many of the disadvantages of their predecessors.

On the one hand, the design remained similar to the mechanics, but the engineers conventionally placed two such mechanical boxes in one housing. One box has even gears, the other odd, and each has a separate clutch.

In short, while the car is moving, for example, in one gear, the next one is also already selected and engaged, but is not engaged, since the clutch is disengaged. At the moment of gear shifting, the working clutch is quickly disengaged, then the second one is instantly engaged. The gear change occurs so quickly that the driver almost does not feel it.

At the same time, the control of such a robot is more reminiscent of the control circuit of an automatic transmission (there is a hydraulic unit called Mechatronic, a larger amount of transmission oil is required, etc.). At the same time, there is also a large number of servomechanisms (similar to a single-disk robot that has one clutch).

The advantages include high fuel efficiency and excellent acceleration dynamics, high level comfort, as well as the better ability of the box to cope with high loads compared to automatic transmissions and CVTs.

At the same time, the preselective gearbox is complex and expensive to manufacture, has a noticeably shorter service life, and in practice requires intervention earlier than an automatic transmission or a variator. As for repairs, robots of this type only require qualified maintenance; they often also require sets of expensive special equipment to carry out many procedures (for example,).

How to distinguish a robot from an automatic or CVT

The fact is that manufacturers strive to simplify as much as possible the entire process of interaction between the driver and the gearbox. For this reason, for example, a robot may have the same selector and modes (P-R-N-D) as a CVT or automatic transmission.

As for the driving sensations (provided that the transmission and the car itself are in full working order), you can pay attention to the following:

AT - often means hydromechanical automatic;
CVT - variable speed transmission;
AMT - robotic gearbox with one clutch;

You can also ask a question on specialized auto forums, study technical literature separately, etc.

Let's sum it up

As you can see, each automatic transmission has both strengths and weaknesses. Also, taking into account the diversity, you may encounter the fact that it can be difficult to immediately determine which automatic transmission is installed on a particular car.

Finally, we note that during operation it is important to separately take into account certain features of a particular machine, depending on the type of transmission and type of automatic transmission. It is also necessary to strictly follow the rules for servicing the automatic transmission, which allows you to increase the resource of the unit.

Automatic safety switches: classification and differences

Beyond Devices protective shutdown, which are not used individually, there are 3 types of network circuit breakers. They work with loads different sizes and differ from each other in their design. These include:

Modular AB. These devices are installed in household networks in which negligible currents flow. Typically have 1 or 2 poles and a width that is a multiple of 1.75 cm.

Molded switches. They are designed to operate in industrial networks with currents up to 1 kA. They are made in a cast case, which is why they got their name.
Air electric machines. These devices can have 3 or 4 poles and can handle currents up to 6.3 kA. Used in electrical circuits with high power installations.

There is another type of circuit breaker for protecting the electrical network - differential. We do not consider them separately, since such devices are ordinary circuit breakers that include an RCD.

Types of releases

Releases are the main operating components of the automatic circuit breaker. Their task is to break the circuit when the permissible current value is exceeded, thereby stopping the supply of electricity to it. There are two main types of these devices, differing from each other in the principle of tripping:

Electromagnetic.
Thermal.

Electromagnetic type releases provide almost instantaneous operation circuit breaker and de-energizing a section of the circuit when a short circuit overcurrent occurs in it.

They are a coil (solenoid) with a core that is drawn inward under the influence of a large current and causes the tripping element to operate.

The main part of the thermal release is a bimetallic plate. When a current exceeding the rated value of the protective device passes through the circuit breaker, the plate begins to heat up and, bending to the side, touches the disconnecting element, which trips and de-energizes the circuit. The time it takes for the thermal release to operate depends on the magnitude of the overload current passing through the plate.

Some modern devices are equipped as an addition with minimum (zero) releases. They perform the function of turning off the AV when the voltage drops below the limit value corresponding to the technical data of the device. There are also remote releases, with the help of which you can not only turn off, but also turn on the AV, without even going to the distribution board.

The presence of these options significantly increases the cost of the device.

Number of poles

As already mentioned, the circuit breaker has poles - from one to four.

Selecting a device for a circuit based on their number is not at all difficult; you just need to know where they are used various types AB:

Single-pole circuits are installed to protect lines that include sockets and lighting fixtures. They are mounted on the phase wire without touching the neutral wire.
The two-terminal network must be included in the circuit to which household appliances with sufficiently high power are connected (boilers, washing machines, electric stoves).
Three-terminal networks are installed in semi-industrial networks, to which devices such as well pumps or auto repair shop equipment can be connected.
Four-pole AVs allow you to protect electrical wiring with four cables from short circuits and overloads.

The use of machines of different polarities is shown in the following video:

Characteristics of circuit breakers

There is another classification of machines - according to their characteristics. This indicator indicates the degree of sensitivity of the protective device to exceeding the rated current. The corresponding marking will show how quickly the device will react in the event of an increase in current. Some types of AVs work instantly, while others will take some time.

There is the following marking of devices according to their sensitivity:

A. Switches of this type are the most sensitive and react instantly to increased load. They are practically not installed in household networks, using them to protect circuits that include high-precision equipment.
B. These machines operate when the current increases with a slight delay. They are usually included in lines with expensive household appliances (LCD TVs, computers and others).
C. Such devices are the most common in household networks. They are turned off not immediately after increasing the current strength, but after some time, which makes it possible to normalize it with a slight difference.
D. The sensitivity of these devices to increasing current is the lowest of all types listed. They are most often installed in shields at the line approach to the building. They provide security for apartment automatic machines, and if for some reason they do not work, they turn off the general network.

Features of the selection of machines

Some people think that the most reliable circuit breaker is the one that can handle the most current, and therefore can provide the most protection to the circuit. Based on this logic, you can connect an air-type machine to any network, and all problems will be solved. However, this is not at all true.

To protect circuits with different parameters, it is necessary to install devices with the appropriate capabilities.

Errors in the selection of AB are fraught with unpleasant consequences. If you connect a high-power protective device to a regular household circuit, it will not de-energize the circuit, even when the current significantly exceeds what the cable can withstand. The insulating layer will heat up and then begin to melt, but no shutdown will occur. The fact is that the current strength destructive to the cable will not exceed the AB rating, and the device will “consider” that emergency situation there wasn't. Only when the melted insulation causes a short circuit will the machine turn off, but by then a fire may already have started.

We present a table that shows the ratings of machines for various electrical networks.

If the device is designed for less power than what the line can withstand and which the connected devices have, the circuit will not be able to operate normally. When you turn on the equipment, the AV will constantly knock out, and ultimately, under the influence of high currents, it will fail due to “stuck” contacts.

Visually about the types of circuit breakers in the video:

Conclusion

The circuit breaker, the characteristics and types of which we discussed in this article, is a very important device that protects the electrical line from damage by powerful currents. The operation of networks not protected by automatic circuit breakers is prohibited by the Electrical Installation Rules. The most important thing is to choose the right type of AV that is suitable for a specific network.

It is easier and cheaper to prevent the fire-hazardous consequences of destruction than to bitterly complain about measures not taken. Preventing electrical fires involves installing protective equipment. In the last century, the function of protection against short circuits and the danger of overload was entrusted to porcelain fuses with replaceable fuse links, then automatic traffic jams. However, due to a significant increase in the load on power lines, the situation has changed. It's time to replace outdated devices with reliable machines. In order for the selection of a circuit breaker to result in the acquisition of a device with the appropriate characteristics, information about a number of electrical technical nuances is required.

Why do we need machine guns?

Circuit breakers are devices designed to protect power cable, more precisely, its isolation from melting and loss of integrity. The machines do not protect equipment owners from impacts and do not protect the equipment itself. For these purposes, an RCD is equipped. The task of the machines is to prevent overheating that accompanies the flow of overcurrents to the entrusted section of the circuit. Thanks to their use, the insulation will not melt or be damaged, which means that the wiring will operate normally without the risk of fire.

The operation of circuit breakers is to open the electrical circuit in the event of:

the appearance of short circuit currents (hereinafter short circuit currents);
overload, i.e. the passage of currents through the protected section of the network, the strength of which exceeds the permissible operational value, but is not considered a TKZ;
noticeable reduction or complete disappearance of tension.

The machines guard the section of the chain that follows them. Simply put, they are installed at the input. They protect lighting lines and sockets, lines for connecting household equipment and electric motors in private homes. These lines are laid with cables of various sections, because equipment is powered from them different power. Consequently, to protect network sections with unequal parameters, protection devices with unequal capabilities are needed.

If you want to learn how to install socket boxes, we recommend that you read the article

It would seem that you can purchase the most powerful devices without unnecessary hassle. automatic shutdown for installation on each of the lines. The step is completely wrong! And the result will pave a direct “path” to the fire. Protection from the vagaries of electric current is a delicate matter. Therefore, it is better to learn how to choose a circuit breaker and install a device that breaks the circuit when there is a real need for it.

Attention. An overrated circuit breaker will carry currents that are critical to the wiring. It will not disconnect the protected section of the circuit in a timely manner, which will cause the cable insulation to melt or burn.

Automatic machines with reduced characteristics will also present many surprises. They will endlessly break the line when starting up the equipment and will eventually break due to repeated exposure to too much current. The contacts are soldered together, which is called “stuck”.

Design and principle of operation of the machine

It will be difficult to make a choice without understanding the circuit breaker design. Let's see what's hidden in a miniature box made of refractory dielectric plastic.

Releases: their types and purpose

The main working parts of automatic circuit breakers are releases that break the circuit if the standard operating parameters are exceeded. Releases differ in the specificity of their action and in the range of currents to which they must respond. Among their ranks are:

electromagnetic releases, which react almost instantly to the occurrence of a fault and “cut off” the protected section of the network in hundredths or thousandths of a second. They consist of a coil with a spring and a core, which is retracted from the effects of overcurrents. By retracting, the core strains the spring, and it causes the release device to work;
thermal bimetallic releases, acting as a barrier against overloads. They undoubtedly also respond to TKZ, but are required to perform a slightly different function. The task of thermal counterparts is to break the network if currents passing through it exceed the maximum operating parameters of the cable. For example, if a 35A current flows through a wiring designed to carry 16A, the two-metal plate will bend and cause the machine to turn off. Moreover, she will courageously “hold” 19A more than an hour. But 23A won’t be able to “tolerate” for an hour; it will work earlier;
semiconductor releases are rarely used in household machines. However, they can serve as the working body of a protective switch at the input private house or on the line of a powerful electric motor. Measurement and recording of abnormal current in them is carried out by transformers if the device is installed on the network AC, or choke amplifiers, if the device is included in the line DC. The decoupling is carried out by a block of semiconductor relays.

There are also zero or minimum releases, most often used as a supplement. They disconnect the network when the voltage drops to any limit value specified in the data sheet. A good option are remote releases that allow you to turn the machine off and on without opening the control cabinet, and locks that lock the “off” position. It is worth considering that equipping with these useful additions significantly affects the price of the device.

Automatic machines used in everyday life are most often equipped with a smoothly working combination of an electromagnetic and thermal release. Devices with one of these devices are much less common and used. Still, combined type circuit breakers are more practical: two in one is more profitable in every sense.

Extremely Important Additions

There are no useless components in the design of the circuit breaker. All components work diligently in the name of overall safety, these are:

an arc extinguishing device mounted on each pole of the machine, of which there are from one to four pieces. It is a chamber in which, by definition, the electric arc that occurs when the power contacts are forced to open is extinguished. Copper-plated steel plates are located in parallel in the chamber, dividing the arc into small parts. The fragmented threat to the fusible parts of the machine in the arc extinguishing system cools down and completely disappears. Combustion products are removed through gas outlet channels. An addition is a spark arrester;
a system of contacts, divided into fixed ones, mounted in the housing, and movable ones, hingedly attached to the axle shafts of the levers of the opening mechanisms;
calibration screw, with which the thermal release is adjusted at the factory;
a mechanism with the traditional inscription “on/off” with a corresponding function and with a handle intended for implementation;
connection terminals and other devices for connection and installation.

This is what the arc extinguishing process looks like:

Let's linger a little on power contacts. The fixed version is soldered with electromechanical silver, which optimizes the electrical wear resistance of the switch. When an unscrupulous manufacturer uses a cheap silver alloy, the weight of the product decreases. Silver-plated brass is sometimes used. “Substitutes” are lighter than standard metal, which is why a high-quality device from a reputable brand weighs slightly more than its “left-hand” analogue. It is important to note that when replacing silver soldering of fixed contacts with cheap alloys, the service life of the machine is reduced. It will withstand fewer cycles of turning off and then turning on.

Let's decide on the number of poles

It has already been mentioned that this protection device can have from 1 to 4 poles. Selecting the number of machine poles is as easy as shelling pears, because it all depends on its purpose of use:

A single-pole circuit breaker will do an excellent job of protecting lighting lines and sockets. Mounted only on a phase, no zeros!;
a two-pole switch will protect the cable supplying electric stoves, washing machines and water heaters. If there are no powerful household appliances in the house, they are placed on a line from the panel to the entrance to the apartment;
a three-pole device is required for three-phase wiring equipment. This is already semi-industrial scale. In everyday life there may be a workshop or well pump line. A three-pole device must not be connected to the ground wire. He must always be in full combat readiness;
Four-pole circuit breakers are used to protect four-wire wiring from fire.

If you plan to protect the wiring of an apartment, bathhouse, or house using two-pole and single-pole circuit breakers, first install a two-pole device, then a single-pole device with the maximum rating, then in descending order. The “ranking” principle: from the more powerful component to the weaker but sensitive one.

Labeling – food for thought

We figured out the structure and operating principle of the machines. We found out what and why. Now let’s boldly begin to analyze the markings affixed to each circuit breaker, regardless of the logo and country of origin.

The main reference point is the denomination

Because The purpose of purchasing and installing a machine is to protect the wiring, so first of all you need to focus on its characteristics. The current flowing through the wires heats the cable in proportion to the resistance of its current-carrying core. In short, the thicker the core, the greater the current that can pass through it without melting the insulation.

In accordance with the maximum value of the current transported by the cable, the rating of the automatic shutdown device is selected. There is no need to calculate anything; the interdependent values of electrical installation devices and wiring by caring electricians have long been summarized in the table:

The tabular information should be slightly adjusted according to domestic realities. The predominant number of household sockets are designed to connect a wire with a 2.5 mm² core, which, according to the table, suggests the possibility of installing a machine with a rating of 25A. The actual rating of the outlet itself is only 16A, which means you need to buy a circuit breaker with a rating equal to the rating of the outlet.

A similar adjustment should be made if there are doubts about the quality of the existing wiring. If there are suspicions that the cable cross-section may not correspond to the size specified by the manufacturer, it is better to play it safe and take a machine whose nominal value is one position lower than the table value. For example: according to the table, an 18A machine is suitable for cable protection, but we’ll take a 16A one, because we bought the wire from Vasya at the market.

Calibrated characteristic of the device rating

This characteristic is the operating parameters of a thermal release or its semiconductor analogue. It is a coefficient by which we multiply to obtain the overload current that the device may or may not hold for a certain period of time. The value of the calibrated characteristic is established during the production process and cannot be adjusted at home. They select it from the standard range.

The calibrated characteristic indicates how long and what kind of overload the machine can withstand without disconnecting the circuit section from the power supply. Usually these are two numbers:

the lowest value indicates that the machine will pass current with parameters exceeding the standard for more than an hour. For example: a 25A circuit breaker will pass a current of 33A for more than an hour without disconnecting the protected section of wiring;
the highest value is the limit beyond which shutdown will occur in less than an hour. The device indicated in the example will quickly turn off at a current of 37 amperes or more.

If the wiring runs in a groove formed in a wall with impressive insulation, the cable will practically not cool during overload and the accompanying overheating. This means that in an hour the wiring can suffer quite a bit. Maybe no one will immediately notice the result of the excess, but the service life of the wires will be significantly reduced. Therefore, for hidden wiring We will look for a switch with minimal calibration characteristics. For the open version, you don’t have to focus too much on this value.

Setting – instantaneous response indicator

This number on the body is a characteristic of the operation of the electromagnetic release. It indicates the maximum value of the abnormal current, which during repeated shutdowns will not affect the performance of the device. It is normalized in units of current, and is indicated in numbers or Latin letters. With numbers, everything is extremely simple: this is the face value. Here's the hidden meaning letter designations It's worth finding out.

Letters are stamped on machines made according to DIN standards. They indicate the multiple of the maximum current that occurs when the equipment is turned on. A current that is several times greater than the operating characteristics of the circuit, but does not cause a shutdown and does not render the device unusable. Simply, how many times the equipment switching current can exceed the rating of the device and cable without dangerous consequences.

For circuit breakers used in everyday life, these are:

IN– designation of machines capable of reacting without self-damage to currents exceeding the nominal value in the range from 3 to 5 times. Very suitable for equipping old buildings and rural areas. They are not used often, because trading network are most often a custom item;
WITH– designation of these protective equipment, the response range of which is from 5 to 10 times. The most common option, in demand in new buildings and new country houses with autonomous communications;
D- designation of switches that instantly break the network when a current is supplied with a force exceeding the nominal value from 10 to 14, sometimes up to 20 times. Devices with such characteristics are needed only to protect the wiring of powerful electric motors.

There are variations abroad, both higher and lower, but the average owner of domestic property should not be interested in them.

Current limiting class and its meaning

Let's talk about this briefly, because most of the devices offered by trade belong to the 3rd class of current limitation. Occasionally there is a second one. This is an indicator of the speed of the device. The higher it is, the faster the device will respond to TKZ.

There is a lot of information, but without it it will be difficult to choose the right circuit breaker and protect property from unwanted fires. Information is also needed for those who will order the installation of protection devices. After all, not every electrician who positions himself as a great specialist should be trusted unconditionally.

Automation of production is a process in the development of machine production in which management and control functions previously performed by humans are transferred to instruments and automatic devices. The introduction of automation in production can significantly increase labor productivity and the quality of products, and reduce the share of workers employed in various areas of production.

Before the introduction of automation tools, the replacement of physical labor occurred through the mechanization of main and auxiliary operations production process. Intellectual labor remained non-mechanized (manual) for a long time. Currently, operations of physical and intellectual labor that can be formalized are becoming the object of mechanization and automation.

Modern production systems Options that provide flexibility in automated production include:

· CNC machines, which first appeared on the market back in 1955. Mass distribution began only with the use of microprocessors.

· Industrial robots, first introduced in 1962. Mass distribution is associated with the development of microelectronics.

· Robotic technological complex (RTC), which first appeared on the market back in 1970-80. Mass distribution began with the use of programmable control systems.

· Flexible production systems, characterized by a combination of technological units and computer-controlled robots, equipped with equipment for moving workpieces and changing tools.

Automated warehouse systems Automated Storage and Retrieval Systems, AS/RS). They involve the use of computer-controlled lifting and transport devices that place products in a warehouse and remove them from there on command.

· Computer-based quality control systems Computer-aided Quality Control, CAQ) is the technical application of computers and computer-controlled machines for testing the quality of products.

· Computer-aided design system (English) Computer-aided Design, CAD) is used by designers when developing new products and technical and economic documentation.

· Planning and coordination individual elements plan using a computer Computer-aided Planning, CAP). SAR- divided by various characteristics and appointments, according to the condition of approximately identical elements.

COMPUTER (electronic computer)

Outline the main provisions of the technology of cleaning and washing operations. Compare cleaning and washing equipment and justify its choice. Evaluate the possibilities of designing a cleaning and washing station.

Washing work is often performed manually using a hose with a gun and a low (0.3-0.4 MPa) or high (1.5-2.0 MPa) pressure pump or mechanized way using washing facilities. A progressive method is mechanized and automatic washing of cars, automotive components and parts, which allows for maximum replacement manual labor and increase labor productivity with high-quality washing.

So, let's look at the main existing species car washes:

Hand washing is a traditional car wash that is performed by people. The car is washed with water and car shampoo using sponges, brushes, rags, etc., that is, contact washing.

The advantage of manual car washing is that during the work process a person sees which areas are more dirty and need more thorough cleaning.

Disadvantages: with such a wash there is a high risk of damaging the paintwork on the car body; and hand washing a car will take greatest number time.

A brush car wash is a contact wash that does not involve people; it is carried out using special automatic installations. The process consists of several stages: first, the machine is sprayed with water under pressure, then with hot foam, then quickly rotating brushes are used to clean the machine from dirt. The last step is to apply protective wax and dry the car.

A brush wash is suitable for heavy soiling that a touchless wash may not be able to handle. Brushes are made from synthetic threads, rounded at the ends. High-quality brushes should not scratch the paintwork.

Contactless car wash is a car wash with active foams. This technology is used on conventional touchless car washes, where washing is carried out by people using special devices, as well as in conveyor and portal car washes. In the process of such washing, the main layer of dirt is washed off with a stream of water under high pressure, then special equipment active foam is applied, under the influence of which the remaining dirt lags behind the body, and after some time the foam is also washed off with a stream of water under pressure. As a rule, such a wash ends with the application of a protective polish, which will add an attractive shine and protect against rapid contamination and harmful effects. environment.

A touchless or high-pressure car wash causes the least damage to the paintwork of the body.

Dry washing is washing with a special shampoo-polish. Car enthusiasts do this type of washing with their own hands. This type of washing does not require water. Manufacturers of dry wash shampoos claim that the silicone oil and surfactants included in the shampoo soften, impregnate and envelop dirt particles, ensuring integrity paint coating with this type of washing. Dry washing will provide shine and protection of the body from negative environmental factors for some time.

The disadvantage of such a wash is the impossibility or inconvenience of cleaning hard-to-reach areas of the car. Therefore, this type of washing is recommended to be used in the intervals between water washes to maintain the cleanliness and tidiness of the car.

There are two types of automatic car washes:

Conveyor type (or tunnel). This is when a car is slowly transported by a conveyor through several arches with various functions cleaning and rinsing (for example: pre-wash, wheel wash, underbody wash, high pressure wash, drying).

The biggest advantage of such car washes is the speed of operation and high productivity. All arches work simultaneously, so the driver does not have to wait until the previous car goes through all the procedures.

Portal type. During such a wash, the car stands still, and the portal (washing arch) moves relative to it.

The disadvantage compared to a conveyor car wash is that a gantry car wash is not able to quickly accommodate such a number of cars.

Outline the main provisions of the technology of diagnostic work. Compare diagnostic equipment and justify its choice. Evaluate the possibilities of designing a diagnostic work station

1.1. The Guide sets out the main provisions for organizing diagnostics of the technical condition of rolling stock of road transport in passenger cars, trucks, buses and mixed motor transport enterprises (ATPs) of various capacities.

1.2. Technical diagnostics is part technological process technical maintenance (MOT) and repair (R) of cars, the main method of carrying out control and control work. In the technical service management system of the ATP, diagnostics is an information subsystem.

1.3. The organization of vehicle diagnostics is based on the planned preventative maintenance and repair system in force in the USSR, set out in the “Regulations on the maintenance and repair of rolling stock of motor transport”.

1.4. In the conditions of ATP, technical diagnostics should solve the following tasks:

Clarification of failures and malfunctions identified during operation;

Identification of vehicles whose technical condition does not meet traffic safety and environmental protection requirements;

Identification of malfunctions before maintenance, the elimination of which requires labor-intensive repair or adjustment work in the current repair area (TR);

Clarification of the nature and causes of failures or malfunctions identified during maintenance and repair;

Forecasting the trouble-free operation of units, systems and the vehicle as a whole within the range between inspections;

Providing information about technical condition rolling stock for planning, preparing and managing the production of maintenance and repair;

Quality control of performed maintenance and repair work.

Vehicle diagnostic technology contains: list and sequence of operations, repeatability factors, labor intensity, type of work, tools and equipment used, technical conditions for performing work.

3.2. Depending on the shift program and the type of rolling stock, diagnostic work is carried out at individual posts (dead-end or passage) or posts located in a line.

3.3. The technology is compiled separately for types of diagnostics D-1, D-2 and others.

3.4. For specialized repair, adjustment and diagnostic stations Dr technology is compiled according to individual diagnosed units, systems and types of work (brake system, steering, wheel alignment angles, wheel balancing, headlight installation, etc.).

3.5. When developing diagnostic technology, one should be guided by established lists of diagnostic operations by type of diagnosis (Appendices 1, 2), which are part of tests given in the current Regulations on the maintenance and repair of rolling stock of road transport, as well as a list of diagnostic signs (parameters) and their limit values(Appendix 5).

3.6. A typical diagnostic technology should contain preparatory work performed before diagnosis, the actual diagnosis, adjustment and final works performed based on diagnostic results.

3.7. Diagnostic technology D-1 and D-2 is compiled taking into account specific conditions ATP.

3.8. Diagnostics at posts (lines) in the scope of D-1 and D-2 are performed by diagnostic operators or diagnostic mechanics. To assist them, they are assigned drivers-transporters, who, in addition to driving vehicles during the diagnostic process, are engaged in placing vehicles at diagnostic stations, removing them from them, driving them to the appropriate area (storage, waiting, maintenance and repair), as well as preparatory and some adjustment work . In an ATP, where there are no full-time ferry drivers, this work is assigned to the drivers of diagnosed vehicles or convoy mechanics who have the right to drive.

Control and diagnostic (Dr) and adjustment operations at maintenance and repair posts are carried out by repair workers.

3.9. At posts (lines) D-1 and D-2 renovation work, related to the elimination of identified faults, as a rule, are not carried out. The exception is adjustment work, the implementation of which during the diagnostic process is provided for by the technological process.

3.10. Perform diagnostic operations before technical maintenance and routine repairs are mandatory, regardless of the availability of diagnostic tools. In the absence of the latter in the ATP, the control and diagnostic operations provided for in this “Manual...” are performed subjectively by a mechanic-diagnostician in order to identify the required volumes current repairs performed before maintenance.