A few years ago I urgently needed to measure the engine speed, and no tachometer! How to be here? Since I needed to measure the turnups, I needed, the option to order a tachometer and wait for it a month, I did not suit me. I had to think! And I came to mind the idea to use a computer for this purpose, or rather - the sound editor installed on the computer.

The audio editor "Adobe Audition" has been set for a long time for working with sound. Therefore, it remains to come up with a way of connecting the engine with a computer. This question was solved literally for 1 minute - IR LED receiver! We climbed into the box and pulled out the LED, as well as the plug "mini jack". I found a piece of microphone cable and after 10 minutes the LED sensor was ready! I put the diode in the clusters from the fountain pen.

Cable assembly.

To illuminate the IR LED sensor used a flashlight. Too LED.

The sensor glued a piece of tape on the nose model, and the flashlight just kept his hand. The distance between the sensor and the lantern 5 ..... 7 cm. The light flux from the flashlight illuminates the receiving LED, and the air screw interrupts (modulates) the light flux. As a result, the LED generates pulses. The sensor is connected to the microphone audio card input. The voltage required for the operation of the LED is ensured by the design of the microphone sound card socket. Any sound card is designed to work including with an electret microphone, since it needs a supply voltage + 5 volts. Therefore, this tension is present on central contact
microphone nest and enters the LED, which ensures its work. As a result, the pulses arising from the rotation of the air screw, through the microphone entering the audio card, and the "Adobe Audition" editor writes all this as a normal sound file.

To measure the engine speed, the record is sufficiently implemented within a few seconds. It's enough. That's what we will see on the screen in the audio editor window.

First of all, I want to note that at the bottom of the editor there is a temporary scale, it is precisely the engine turnover. In this case, the recording time was 9 seconds. The arrow shows the editor at the bottom of the timeline. Now you need to consolidate the scope of the sound file. In order not to read it in one second, it is for a long time to count), we calculate them for a period of time 0.1 seconds, and then multiply by 10. At first, on the timeline, we choose the recording site just over 0.5 seconds and stretch it on the entire screen.

Selected section ~ 0.5 seconds stretch over the entire screen. The timeline also stretched out.

Now on the timeline allocate a length of time smooth 0.1 sec - from 3.1 to 3.2 seconds.

and also stretch it on the whole screen. Now clear impulses are visible, calculated that is not difficult.

We consider pulses in the time interval of 0.1 sec. - They are 42.

And now simple arithmetic. Once in 0.1 sec. We have 42 impulses, it means for 1 sec. They came from the sensor 420. And in 1 minute 420 x 60 seconds. \u003d 25200 pulses. But so the ka screw has 2 blades and interrupts the light stream twice, the result must be divided into 2 and get 12,600 revolutions per minute. What was required to determine. In the case of a 3-blade screw, the result is divided by 3. In the case of a 4-blade screw, we divide on 4. Such an unusual tachometer - the synthesis of the IR diode, the computer and the sound editor quite satisfying me! And the question of the acquisition of the "iron" tachometer in the store,
I saw myself. And from the acquisition refused.
On the flights in the Tachometer field, I do not need, and at home the computer and the cable with the LED is always at hand.
I think that not all colleagues have a tachometer at home, but I want to measure the engine speed! In this case, my experience, I hope, comrades will come in handy. "Adobe Audition" You can download for free from here http://www.fayloobmennik.net/2293677. You can use another sound editor to whom you like. My sound file of this engine test, recorded by the editor lies here. In this article, I wanted to show that if necessary, if you want to want a lot, in most cases, which arise from us, modelists, you can come up with a decent substitution of the necessary, but missing, to the device. I hope Chinese comrades are not in disadvantage.

When buying an electric motor with hands, it is not necessary to count on the presence of technical documentation. Then the question arises on how to find out the number of revolutions of the acquired device. You can trust the seller's words, but good faith is not always their distinctive feature.

Then the problem arises with the determination of the number of revolutions. It can be solved, knowing some subtleties of the engine device. This will be discussed further.

Determine the revs

There are several ways to measure the revolutions of the electric motor. The most reliable is to use a tachometer - a device intended for these purposes. However, such a device is not every person, especially if he does not engage in electric motors professionally. Therefore, there are several other options to cope with the task of "on the eye".

The first implies the removal of one of the engine covers in order to detect the winding coil. The latter may be somewhat. The one is selected that is more accessible and located in the visibility zone. The main thing, while working prevent the integrity of the device during operation.

When the coil opened a breath, it is necessary to carefully inspect it and try to compare the size with the stator ring. The latter is a fixed element of the electric motor, and the rotor, while inside it, rotates.

When the ring is half closed with a coil, the number of revolutions per minute reaches 3000. If the third part of the ring is closed - the number of revolutions is approximately 1500. With a quarter - the number of revolutions is 1000.

The second method is associated with windings inside the stator. The number of grooves that one section of any coil occupies is considered. The grooves are located on the core, their number indicates the number of pairs of poles. 3000 revolutions per minute will be with two pairs of poles, at four - 1500 revolutions, at six - 1000.

The answer to the question of which depends on the number of revolutions of the electric motor, there will be a statement: from the number of pairs of poles, and this is inversely proportional dependence.

On the housing of any factory engine there is a metal tag on which all characteristics are indicated. In practice, such a tag may be absent or stealing that it complicates a little complicates the task of determining the number of revolutions.

Correct revs

Working with a variety of electric tools and equipment in everyday life or at work will certainly raises the question of how to adjust the speed of the electric motor. For example, it becomes necessary to change the speed of the movement of parts in the machine or by pipeline, adjust the performance of pumps, reduce or increase air flow in air ventilation systems.

To carry out these procedures by lowering the voltage is practically meaningless, the turnover will fall sharply, the power of the device will significantly reduce. Therefore, special devices are used to adjust the engine speed. Consider them in more detail.

Frequency converters act as reliable devices that can radically change the frequency of the current and the signal form. Their foundation consists of semiconductor triodes (transistors) of high power and pulse modulator.

The microcontroller manages the entire process of operation of the converter. Thanks to this approach, it appears to achieve a smooth increase in engine speed, which is extremely important in mechanisms with a large load. Slow acceleration reduces the load, positively affecting the service life of industrial and household equipment.

All converters are equipped with protection with several degrees. Part of the models operates due to single-phase voltage in 220 V. The question arises, is it possible to make the three-phase motor to rotate thanks to one phase? The answer will be positive subject to the following condition.

When a single-phase voltage is applied to the winding, the "push" of the rotor is required, since it does not move off. This requires a starting capacitor. After the start of the engine rotation, the remaining windings will give the missing voltage.

A significant disadvantage of such a scheme is considered a strong phase skew. However, it is easily compensated by inclusion in the autotransformer scheme. In general, this is a rather difficult scheme. The advantage of the frequency converter is the ability to connect asynchronous type motors without the use of complex schemes.

What gives the converter?

The need to use the rotor controller in the case of asynchronous models is as follows:

Significant electrical energy savings are achieved. Since not all equipment requires high speeds of rotation of the engine shaft, it makes sense to reduce the quarter.

Provides reliable protection of all mechanisms. The frequency converter allows you to control not only the temperature, but also pressure and other system parameters. This fact is especially important if the pump is driven by the engine.

The pressure sensor is set in the container, sends a signal when the proper level is reached, so that the motor stops.

A smooth start is performed. Thanks to the regulator, the need to use additional electronic devices is removed. The frequency converter is easy to configure and get the desired effect.

The costs of maintenance are reduced, since the regulator minimizes the risks of drive breakage and other mechanisms.

Thus, electric motors with a regulator of revolutions turn out to be reliable devices with a wide range of applications.

It is important to remember that the operation of any equipment based on an electric motor only will be correct and secure when the rotational speed parameter will be adequate to the conditions of use.

Photo of turns of the electric motor

Each vehicle with an internal combustion engine is equipped with an instrument for measuring the rotational speed of the crankshaft - tachometer. What a tachometer is and why it is needed, what tachometers are used today on the vehicle, as they are arranged and work - read in this article.

What is a tachometer and why is it needed in a car?

Automotive - instrument for measuring and displaying the rotational speed of the crankshaft engine. The device constantly displays the current power units, which allows you to solve several tasks:

• Select the optimal gearbox and vehicle speed in various conditions. It is according to the testimony of a tachometer, the easiest way to choose the right moment to switch from the lowest to the highest transmission and vice versa;
• Select the optimal mode of operation of the engine. Internal combustion engines develop the largest torque in a narrow crankshaft speed interval, and it is from the tachometer that it is easiest to track the achievement of this regime;
• To identify malfunctions in a timely manner, leading to uneven operation of the engine at idle and in all modes. Some malfunctions of the power supply system, ignition and other systems lead to the fact that the engine turnover? Swim?, What is easy to track along the tachometer.

Despite the widespread introduction of electronic control systems that choose the optimal modes of operation of the motor with changing loads, tachometers do not lose their relevance. This device is essential for the proper operation of vehicles, so today it is necessarily present on passenger and trucks, tractors and special equipment.

Types and types of tachometers

Tachometers used on transport are divided into several types on the principle of operation, a method for processing a signal and an indication, a method for connecting and applicability.

According to the principle of operation and the method of connecting, tachometers are:

• Mechanical / electromechanical (centrifugal, magnetic) with direct drive;
• Electrical connected to the engine ignition system - electronic (pulse);
• Electric with connection to an electrical generator - electromashic.

Connecting an electronic tachometer to the contactless ignition system

Connecting an electronic tachometer to the ignition contact system

According to the method of signal processing, tachometers are analog and digital.

Under the applicability, tachometers are divided into several groups:

• For gasoline engines with a contact and contactless ignition system - connection directly to the primary (low-voltage) chain;
• For all types of engines with an electronic control unit - connection to the ECU, the block itself uses to control the tachometer signals from the ignition system or the crankshaft position sensor;
• For diesel engines - connect to the generator.

As a rule, tachometers are manufactured for operation on certain brands and models of cars, tractors and other equipment, some devices can be used on various transport, equipped with the same engines, ignition systems, etc.

Tachometer device

It consists of several main nodes: a measuring unit or a signal converter, an indication unit and auxiliary components.

The measuring unit of mechanical and electromechanical tachometers is most often a magnetic, similar to the usual speedometer (in essence, speedometer and is a tachometer measuring the frequency of rotation of the secondary shaft of the gearbox or wheels). Such a speedometer connects to the engine flexible shaft.

The measuring unit in electrical devices can be built according to analog schema engineering on transistors or on digital circuit engineering based on specialized microcircuits. This unit receives a signal from the sensor, the computer, the generator, or the ignition system, processes it in accordance with the pre-settings, and the converted signal feeds to the indication unit.

The indication unit may be several types:

• The arrow indicator (with the leading arrow with a milliammeter);
• Digital indicator based on a liquid crystal or LED display;
• Indicators with a linear LED scale - the role of the arrow performs a line of different color LEDs.

On cars are commonly used shooter indicators that are better read and allow you to immediately determine how the engine works in which mode. Digital and LED indicators are most often installed in tuning, they also find use in simple tachometers for motorcycles, diesel generators, etc.

The tachometer scale is divided into several zones marked with different colors:

• Zone of small revolutions - In this circuit range, the engine is unstable, the zone can be marked in red;
• Zone of optimal revolutions (? Green zone?) - In this range, the engine develops the largest power and torque, the zone is usually marked with green;
• Zone of increased revolutions - this range of revolutions is conditionally dangerous for the engine, usually this zone is marked with yellow or a feature over the red zone;
• The high speed zone (? Red zone?) - This rolver range is dangerous, the engine works with overload and works with low efficiency, this zone is marked in red.

The gradation of the speed scale can be performed in units or in dozens, indicating the multiplier - x100 or x1000, the speed unit is R / min or MIN -1.

The entire design is placed in a housing that can be mounted in the dashboard or installed separately. At the same time, tachometers can be different by configuration:

• Device without additional functions;
• Tachometer with various indicators;
• Tachometer combined in one case with other devices - speedometer, odometer, motor meter, etc.

Separately, you need to tell about the principle of operation of the most common types of tachometers.

The principle of operation of magnetic tachometers

The operation of the magnetic tachometer is based on the phenomenon induction of vortex currents (Foucault currents) in a non-magnetic disk with a rotating constant field. In the usual condition, the aluminum or copper disk does not have magnetic properties, but if you place it in a rotating magnetic field, then the vortex currents occur. These currents interact with the magnetic field, so the non-magnetic disk also begins to rotate after the magnet.

For the operation of the tachometer to the disk, an arrow is attached to the shaft of which the return spring is fixed. Magnet is associated with crankshaft or one of the transmission shafts by means of a flexible shaft. The higher the engine turnover, the faster the magnet rotates, and the higher the force, deflecting the fixed spring, the non-magnetic disk - all this is reflected in the position of the arrow.

The principle of operation of electric tachometers

Electrical tachometers are used to measure electrical signals or individual pulses. Electrical signals, proportional to the rotational speed of the crankshaft, in the gasoline engine are generated by the ignition system and an electric generator, and in the gasoline engine only by the generator. Also, the required signal can be obtained from the electronic engine control unit.

The most simply runs the tachometer connected to the electric generator. The generator has a drive from the crankshaft by means of a clinorem transmission, so the frequency of rotation of the generator rotor is always proportional to the engine revolutions. And the magnitude of the generated on the rotor of the generator depends on the rotation frequency of the generator, which is used to connect the electromasone tachometer. In essence, the device is a voltmeter that will measure the voltage on the generator and transforms it in the testimony of the number of crankshaft. The tachometer connects to the generator through a special connector, and the instrument is required for a specific generator.

The operation of the electronic tachometer connected to the ignition system is slightly more complex. In the ignition system, the current pulses are generated to form a spark in ignition candles. At the same time, the frequency of sparking is directly related to the frequent rotation of the crankshaft - otherwise the fuel-air mixture would not be lit in the cylinders on time. The sparking frequency depends on the number of engine cylinders and the order of their work. In four-cylinder engines, the ignition system generates two sparks in one crankshaft turn - on one spark for every 180 °. It is this circumstance that is used to work electron tachometers - the measuring unit measures the frequency of sparking, and transforms it in the indication of the number of rotation of the engine. The electronic tachometer is connected to the primary (low-voltage) ignition circuit, and measures the number of pulses per unit of time, so this type of instruments are often called pulsed.

In the same principle, simple tachometers for motorcycles and other devices with single or two-cylinder two-strokes are operating, but such devices are connected to the high-voltage part of the ignition system. Connection - with a wire, accused around high-voltage (candle) wires. In this case, the number of pulses on the candle is measured directly and this parameter is converted to the rotation of the rotation of the motor.

- The device is simple and reliable, this device can work safely throughout the life of the vehicle. But in the event of a breakdown, the device should be replaced as soon as possible - only in this case the engine operation and the operation of the vehicle will be ensured in optimal mode.

Among the general industrial used for accounting for products and raw materials, commodity, automobile, carriage, trolley, etc. technological serve for weighing products during production with technologically continuous and periodic processes. Laboratory is used to determine the humidity of materials and semi-finished products, conducting physicochemical analysis of raw materials and other purposes. There are technical, exemplary, analytical and microanalitric.

It can be divided into a number of types, depending on the physical phenomena, on which the principle of their action is based. The most common devices for magnetoelectric, electromagnetic, electrodynamic, ferrodynamic and induction systems are most common.

The diagram of the device of the magnetoelectric system is shown in Fig. one.

The fixed part consists of a magnet 6 and magnetic pipeline 4 with pole tips 11 and 15, between which a strictly centered steel cylinder is installed in the gap between the cylinder and the pole tips, where the uniform radially directional is focused, a frame of a thin isolated copper wire is placed.

The frame is reinforced on two axes with cores 10 and 14, resting in the spyers 1 and 8. The opposing springs 9 and 17 serve as current supplies connecting the winding of the frame with the electrical circuit and the input clamps of the device. On the axis 4, the arrow 3 with balanced weights 16 and the opposing spring 17, connected to the recording lever 2.

01.04.2019

1. Principle of active radar.
2. Pulse radar. Principle of operation.
3. The main temporary ratio of the operation of the pulse radar.
4.Vides RLS orientation.
5. Forming a sweep on IOK RLS.
6. Principle of functioning of induction lag.
7.Vids of absolute lags. Hydroacoustic Doppler Lag.
8.Registrator of the flight data. Work description.
9.Arts and the principle of AIS's work.
10. The proceedable and received AIS information.
11.Ganization of radio communications in AIS.
12.Stave the AIS ship equipment.
13. Design scheme of ship AIS.
14. Principle Action SNA GPS.
15. Successful GPS Differential Mode.
16. Error sources in GNSS.
17. Constructive GPS receiver scheme.
18. The effect of ECDIS.
19. Classification of ENC.
20. The appointment and properties of the gyroscope.
21. Principle of the weight of the gyrocompass.
22. Principle of the magnetic compass.

Cable connection - The technological process of obtaining an electrical connection of two cable segments with the restoration of the connection of all protective and insulating shells of the cable and screen braids.

Before connecting cables, the insulation resistance is measured. In unshielded cables for the convenience of measurements, one conclusion of the megaommeter is connected alternately to each core, and the second to the remaining veins connected. The insulation resistance of each shielded core is measured when connecting the conclusions to the core and its screen. Received as a result of measurements must be no less normalized value established for this cable brand.

Having measured the insulation resistance, go to the establishment or numbering of cores, or references, which indicate the arrows on temporarily fixed tags (Fig. 1).

Having finished the preparatory work, you can start cutting cables. The geometry of the cutting of the joints of the cable ends is modified in order to ensure the convenience of the insulation restoration of the veins and the shell, and for multi-cable cables, also to obtain an acceptable sizes of the connection of cables.

Methodological manual for practical work: "Operation of SEU cooling systems"

BY DISCIPLINE: " Operation of energy installations and safe watches in the engine room»

Operation of the cooling system

Cooling system assignment:

• heat removal from DG;
• removal of heat from the auxiliary equipment;
• slip heat to OU and other equipment (DG in front of the launch, the VD maintaining in the "hot" reserve, etc.);
• reception and filtering of intricate water;
• blowing kingston boxes in summer from clogging with jellyfish, algae, mud, in winter - from ice;
• ensuring the work of ice boxes, etc.

Structural cooling system is divided into fresh water and the cooling system of fence water. ADG cooling systems are performed autonomously.

Fig. 1. System cooling diesel engines

1 - fuel cooler; 2 - turbocharger oil cooler; 3 - expansion tank GD; 4 - water cooler GD; 5 - oil cooler GD; 6 - Kingstonic box; 7 - Filters of intricate water; 8 - Kingstonic box; 9 - Filters VDS; 10 - Wound Water Pumps 11 - Pump of fresh water GD; 12 - the main and reserve pumps of the heading water GD; 13 - oil cooler VDS; 14 - Water cooler VDS; 15 - VD; 16 - Expansion tank VDS; 17 - hydrophop reference bearing; 18 - the main stubborn bearing; 19 - main engine; 20 - charge air cooler; 21 - water for cooling compressors; 22 - filling and replenishing the system of fresh water; 23 - Connecting the HRS warming system; 1op - fresh water; 1oz - wicked water.

23.03.2019

In the course of operation, its winding is gradually fails, taking on the impact of various negative factors. Restore engine performance can be rewinding. Follow the procedure when signs of breakdowns occur.

Causes and signs of winding wear

The engine winding is rewinded when such "symptoms" occurs, as an extraneous noise and a knock, accompanied by a violation of the integrity and loss of isolation elasticity. There is a similar reason for several reasons. The main among them are:

• the impact of natural phenomena, including high humidity, temperature fluctuations;
• entering machine oil, dust and other contaminants;
• incorrect operation of the power unit;
• impact on the motor of vibratory loads.

Frequent cause of wear, stretching, the loss of integrity perform temperature moments. When overheated, excessive overvoltage occurs, which makes the winding sensitive to external influences. The slightest blows and vibrations lead to breakdowns.

Also a common cause of the failure of the windings of electric motors is a breakdown of bearings, which due to overloads or due to temporary wear can fly into small pieces, which leads to the combustion of the windings.