Brake electromagnets and electromagnetic clutches. What is an electromagnetic clutch? Application and repair. There are electromagnetic couplings

Model range of Helistar couplings: POC, POB, PFB, PHC, PHB, PLB

The main function of electromagnetic couplings is to transmit torque from the drive shaft to the driven shaft. In this case, there is no need for mechanical contact, since the principle of their operation is based on the interaction of magnetic fields. Presented in this section of the catalog the lineup Helistar couplings(POC, POB, PFB, PHC, PHB, PLB) does not create noise, vibrations, has no wearing parts and is designed for a long service life.

The connection between the driving and driven structural elements is carried out by increasing the degree of viscosity of the mixtures, which fill the gap between the clutch surface of the couplings with an increase in the magnetic flux in this gap. Main component such mixtures - ferromagnetic powder (for example, carbonyl iron). To prevent mechanical destruction of iron particles due to constant exposure to friction or their adhesion, special liquid or bulk fillers are added.

Helistar brand couplings are distinguished by high speed operation, however, their operational reliability indicators are not sufficient for use in such an area of ​​industrial activity as machine tool building. Among the areas in which they are most widely used are food, printing, and packaging.

Helistar range of powder electromagnetic couplings

Model		Name	Kgs-m
	POC	Provide smooth acceleration and braking, reduce overload, and also separate the start of engines and mechanisms		POC	Least susceptible to abrasive inclusions (used for cooling compressed air must be dry and not contaminated with oil)		POB	By changing the voltage in the excitation winding, they provide smooth torque control		POB	The operating principle of the brake is based on the use of electromagnetic forces that act in a gap filled with ferromagnetic powder. Under constant influence magnetic field the powder is drawn into the working gaps of the brake and a mechanical connection is created between the stator and rotor		PFB	Provide precise adjustment of the braking torque regardless of the number of revolutions and have a high range of adjustment of the braking torque		P.H.C.	Single friction surface design avoids braking torque and operates in conditions high temperatures		PHB	The design makes it possible to separate the start of motors and mechanisms, reduce the starting current time, eliminate shocks and ensure smooth acceleration of electric motors, eliminate overloads, slippage, etc.	1.2~20
	PLB	Located between the coupling halves protective screen ensures tightness when pumping products (aggressive, highly toxic, fire and explosive, strong-smelling and other types of liquids)		POC	Compact design with medium torque coupling. Suitable for use in medium and low power equipment		POB	Compact design with low coupling torque. Used in low-power equipment	5~50

Choice suitable model coupling (clutch torque and drive power) is carried out individually and depends on the viscosity of the medium and the intensity of mixing of the product.

If you are interested in purchasing any of the Helistar electromagnetic coupling models presented above, please contact us as soon as possible. in a convenient way. We guarantee qualified assistance in the selection of spare parts that meet your requirements and Supplies, and we will be happy to answer any of your questions. Delivery is carried out in the shortest possible time to all regions of Russia and neighboring countries.

Our electromagnetic powder couplings and brakes have successfully passed CE certification and are used in China Jiuquan Satellite Launch Center.

Our company has a complete set of testing equipment, including torque, speed and power measurement systems to ensure product reliability. We have passed the ISO9001:2000 quality management system certification, and strictly follow the national industrial standards JB/T 5988-1992 and JB/T5989-1922.

Product characteristics
1. Torque varies linearly with field current.
Torque is transmitted through a magnetic powder circuit generated by an electromagnetic field. At normal conditions, the excitation current is in linear relationship with torque, and is transmitted in the range of 5-100% of the rated torque, which is shown in Fig. A. Thus, when the field current changes, the torque changes accordingly.

2. Torque does not depend on sliding speed at constant excitation current.
When the field current remains constant, the transmitted torque does not depend on the sliding speed between the transmission part and the driven link, i.e. there is no difference between static torque and dynamic torque. (See Fig. B) Thus, constant torque is transmitted stably. By using this tension control feature, you can accurately control and transmit the desired torque just by adjusting the drive current. This represents excellent benefit and convenience when controlling the tension of roll materials.

Application
As a versatile, high-performance component automatic control, clutches and brakes are widely used in unwinding tension control in dyeing, printing, spinning, papermaking, tablet making, plastic, rubber, wire and cable manufacturing, metallurgy and other fields involving winding processing. Electromagnetic clutch can also be used for buffer running, overload protection, speed regulation, etc., and the electromagnetic powder brake is used to load and brake the transmission of equipment mechanisms.

Model selection
1. The selection of electromagnetic powder clutches and brakes generally depends on the maximum torque required for the transmission. At the same time, we recommend that you pay attention to the fact that the actual sliding power is less than the permissible one.
Calculation formula:
Actual sliding power P=2×3.14×M×n/60=F·V
M----actual torque, Nm
n----sliding speed, rpm
F----voltage, N
V----linear speed, m/s
In the absence of a speed control mechanism, a device with maximum tension is required to wind the material, and the maximum winding radius must be less than the rated torque of the electromagnetic powder brake.
2.The choice of electromagnetic powder clutch also depends on its position. For appropriate sliding power, a small clutch is suitable if installed in a high-speed application. This allows you to significantly reduce costs. If it is impossible to install a small-sized coupling, you need the product bigger size, which is installed in the middle or rear of the transmission mechanism to increase operating torque and reduce sliding speed.
3. Under certain cooling conditions, the sliding power of the electromagnetic powder clutch or brake is fixed. Thus, the actual torque and speed will cancel each other out, which means that as the sliding speed increases, the permissible torque will correspondingly decrease. However maximum speed should not exceed the permissible value.

Example. Electromagnetic powder brake FZ100, its rated torque is M=100 Nm, and its sliding power is P=7 kW.
Thus, the nominal speed is n=9550×P/M=9550×7/100=668.5 rpm.
At actual sliding speed n=1500 rpm, permissible torque M=9550×P/n=9550×7/1500=44.6 Nm.
Note: 9550 is a constant coefficient.

As a professional electromagnetic powder clutch and brake manufacturer in China, our company also sells the following product ranges: elevator/escalator components, busbar processing equipment, marine cleaning equipment Wastewater, gear hobbing machines, etc.

An important element of various designs can be called a coupling. Modern technological capabilities have made it possible to obtain more complex devices that are characterized by more attractive performance characteristics. Electromagnetic couplings can be called a modern proposal. They are installed on modern cars and many other devices. The rather complex design and complex operating principle determines that you need to clearly understand such a device to ensure its quality service. Let's look at all the features this issue more details.

What is an electric coupling?

An electromagnetic clutch is a special device for solving a wide variety of problems, most of which involve connecting and disconnecting a pair in mesh. Electromagnetic couplings are produced for machine tools and other components of vehicles or diesel locomotives. There are several main types of such structures:

1. Friction type mechanisms are cone and disk.
2. Electromagnetic clutch gear type is considered a specific design option, since the working part is represented by a combination of different teeth.
3. Powder electromagnetic coupling is a modern option as it provides axial displacement when required.

Electro coupling is intermediate connecting element. The principle of operation is to use the basic properties electric current to generate electromotive force.

At the same time, he can perform the most various functions, for example, protecting the main device from overheating or control.

The operating principle of the electromagnetic clutch

The electromagnetic clutch can have the most different designs, but also highlight classic version execution. Its features are as follows:

1. The main elements can be called two rotors, one of which is represented by an iron disk with a thin end protrusion.
2. The internal part is equipped with pole pieces that provide radial displacement. To transmit current, a winding is created and connected to the power source through slip rings. Part of this element is located on the shaft.
3. The magnetic coupling under consideration has a second rotor, which is represented by a cylindrical shaft with special grooves located parallel to the main axis. They are created so that special bars with pole pieces can be inserted.

The coupling in question is on permanent magnets has a rather complex design, which ensures accurate and reliable operation. The operating principle of the device is as follows:

1. When current appears, an electromagnetic field arises, which intersects with the conductor and begins to interact.
2. Such a combination causes the emergence of electromotive force. It may be quite sufficient to move the moving element, taking into account overcoming a certain force.
3. In the manufacture of this part, a copper bar is used, which ensures the closure of the circuit. A current passes through them, due to which an electromagnetic force appears.
4. The resulting fields provide a driven rotor behind the leading one, while the delay is insignificant.

A similar operating principle is used to create the most various mechanisms. In this case, the device of the machine makes it possible to stop the transmission of torque within a few fractions of a second, which determines its distribution.

Demagnetization of the electromagnetic clutch occurs by disconnecting the power source. In this case, the special properties of the material determine that the magnetic field disappears almost immediately, due to which the reverse movement of the moving element occurs. The electromagnet windings used are designed for sufficient a large number of This is the coupling and disengagement of the driving element with the driven element.

When considering what an electromagnetic clutch is, you also need to pay attention to the properties of the materials used in its manufacture.

Only special alloys have magnetic properties that provide the required operating conditions.

The transmission of torque to the clutch can be carried out from electric motor and other similar elements. The dimensions of all dimensions are in most cases standardized, but it is possible to order the production of the mechanism to order. Classification is usually carried out according to the area of ​​application and many other characteristics.

Classification of electric couplings

In most cases, electrofusion couplings are classified according to the area in which they are used. The most commonly used is an electromagnetic friction clutch. It has the following properties:

1. The device can be used to reduce the likelihood of exposure to impulse loads.
2. Idling design features identify minor losses. This point determines that the main elements do not heat up during operation.
3. It is possible to quickly start the mechanism even if it is under heavy load.

The type of mechanism under consideration is divided into several main types:

1. Contact.
2. Brake.
3. Contactless.

Quite often there is an electromagnetic brake clutch, which can reduce the number of revolutions during operation.

Most common last type mechanism. However, it is also classified into several main types:

1. According to the friction indicator, wet and dry are distinguished. IN Lately Versions that can only work with the addition of oil have become widespread.
2. Classification is also carried out according to the switching mode: non-permanent and constant.
3. There are couplings with one or more driven discs. The choice is made depending on the required performance characteristics.
4. Based on the type of control, there are also several main types of mechanism. An example is mechanical, hydraulic and combined.

Electromagnetic powder couplings are included in a separate group. They are represented by a combination of substances that, when interacting, can provide a strong bond.

This modern version execution occurs in the case when it is necessary to ensure the displacement of the connected elements relative to each other at the time of operation.

Safety elements, electromagnetic friction multi-plate clutches

Such an electric coupling is most often installed on machines with a numerical control unit. The advantages include the following points:

1. Compactness. Due to this, it is possible to install the electromagnetic coupling in modern devices. Every year the dimensions of the device are significantly reduced, thereby expanding the scope of application.
2. Reliability. This parameter is considered the most important when choosing almost any coupling. Application special materials and quality control at all stages of production allows us to achieve the highest level of reliability.
3. Small size. This parameter determines ease of transportation and many other positive parameters.

This version is characterized by fairly high performance characteristics, due to which it has become widespread. The main parts of the structure are:

1. Frame. In most cases, it is made using steel, which is characterized increased stability to environmental influences. The purpose of the case is to protect the internal elements.
2. Coil. This element is designed to directly create an electromagnetic field, due to which the main elements are displaced. The coil is designed to withstand a certain electrical current, too high voltage has a negative impact.
3. Friction type disc group. When manufacturing a package of friction discs, a special alloy is used, characterized by certain magnetic properties.
4. Leash and pressure plate.
5. The body has a mounted ring made of insulating material.
6. The current is supplied using a contact brush. It is this that in most cases fails during the operation of the mechanism.

Eliminate the possibility of occurrence short circuit possible using cut holes in the disks. At the moment the electric current is applied, an electromagnetic field is created, which is closed using a friction disk. It is due to this that an attractive force is created, behind which the main part is displaced.

There are several variants of such designs. An example is a device with a remote and magnetically conductive disk.

Advantages of connections using electrofusion couplings

The device in question has become very widespread. This can be attributed to the fact that it has enough big amount benefits that must be taken into account. The following are considered the most important:

1. Reliability. When electrical current is applied, the device disconnects individual elements within a short period of time. In this case, the electromagnetic field is not affected by the environment, so, as a rule, significant problems during operation do not arise.
2. Preservation of basic properties over a long period. An important criterion The choice of such devices can be called precisely the operational life. Due to the use of special materials, this indicator in the case under consideration is significantly expanded.
3. Operation within a few fractions of seconds. This result is typical for a relatively small number of devices in this category. Response time is a parameter that is taken into account when choosing a coupling.
4. Possibility of execution to achieve a variety of purposes, for example, device protection or remote control.
5. Compact and light weight. These parameters are also considered quite important, since too much weight puts a strain on the main structure. Its compactness allows the device to be integrated into a wide variety of designs.

However there are several significant shortcomings, which must be taken into account. An example is that the device is quite expensive, and maintenance should be carried out exclusively by a specialist. In addition, operation if basic recommendations are not followed can cause increased wear. Do not forget that the device requires electric current to operate, which causes the appearance of the required electromagnetic field.

Application area

The device has received very wide use, as it provides the connection of several elements and their separation if necessary. The scope is as follows:

1. Cars and others vehicles have units that are equipped with an electromagnetic coupling.
2. Recently, the device is increasingly being installed in CNC machines. This is due to the fact that their work requires high precision work.
3. Several types of different devices have been developed that can act as an intermediate element. Couplings can be used to achieve a variety of purposes, for example, protecting the device from overheating by turning off the drive when the sensor is triggered.

In general, we can say that the use of electric current to generate a signal can significantly expand the scope of application of the device. This is due to the possibility of transmitting signals from various sensors.

In conclusion, we note that electromagnetic couplings produce the most various organizations. It is recommended to pay attention exclusively to products famous manufacturers, since the declared parameters correspond to the real ones. In production, the most various materials, attention is paid to protection from environmental influences.

25.6. Electromagnetic clutches and brakes

25.6.1. Electromagnetic coupling EMS-750

The electromagnetic coupling EMS-750 is pre-trained for operational control of the drawworks drive and protection of its mechanisms from mechanical overloads. Operating mode - S4. PV - 60%. Climatic performance n placement category - U2 according to GOST 15150-69.

Group of operating conditions - M8 according to GOST 17516-72

Basic technical data of the coupling

Transferable moment, N ■ m.

nominal..... 7350

maximum..... 15 700

Homhiw Chvny 1 ok excitation, A......... 70

Maximum short-term excitation current, A. 110

Rice. 25.27. Dimensional and installation connecting dimensions couplings EMS-750

Rated excitation voltage, V......56

Drive shaft rotation speed, rpm.......750

Nominal slip, %. .5+1.25

Weight, kg.........3400

The outer part of the coupling is an anchor, which is a steel cylinder with annular ribs on outer surface to increase heat transfer. Bearing shields are bolted to the armature, a fan is mounted on one of them, and a semi-shaft is attached to the other, the output end of which is directly connected to the motor shaft. The inductor, located inside the armature, is made of three claw-shaped parts, fastened together and mounted on the shaft. The output ends of the field coils are led out to slip rings through holes in the shaft.

When voltage is applied to the excitation coils, an electromagnetic flux arises in the inductor, which induces eddy currents in the rotating armature. As a result of this interaction, an electromagnetic torque is created, under the influence of which the inductor begins to rotate in the direction of rotation of the armature with a certain slip. The value of the transmitted torque is regulated by the excitation current.

The coupling frame is welded. On the side of the driven shaft, a tachogenerator is located on the frame to control the speed of rotation of the driven shaft. The coupling assembly is closed with a removable casing. General form, overall and installation and connection dimensions of the coupling are shown in Fig. 25.27.

25.6.2. Electromagnetic powder brake TEP 45

Electromagnetic powder brake type TEP 45 is designed to brake and hold the weight of a load released through the actuator. Operating mode - S4. Climatic modification and placement category - U1 according to GOST 15150-69. Designed for use in non-explosive environments environment, which does not contain chemically aggressive impurities that have a harmful effect on the brake insulation.

Group of operating conditions - M18 according to GOST 17516-72.

Brake technical data

Braking torque, kNm:

nominal..... 45

maximum with double boost of excitation current....... 65

Current, A........ 20/5

Power consumption, kW 1.27

The operating principle of the brake is based on the use of electromagnetic forces acting in the brake gap filled with ferromagnetic powder. Under the influence of a constant magnetic flux created by field coils when passing through them direct current, the powder is drawn into the working gaps of the brake,

Rice. 25.28. Overall and installation-connection dimensions of the TEP-45 brake

creating a mechanical connection between the stator and rotor. After the field coils are turned off, the magnetic flux disappears, the powder is ejected from the air gaps and the rotor is disengaged from the stator.

The brake consists of two inductors fastened together and a T-shaped armature mounted on a shaft. Inside the inductors there are excitation coils, the output ends of which are brought out to the terminal box. To remove heat from core There are axial channels in the body of the inductors, and annular grooves at the ends. Bearing shields with inspection holes closed with covers are welded into the internal holes of the inductors. The inductors connected to each other form the brake body. A tachogenerator is mounted on the brake stator, which is driven through a chain drive. To remove powder from the brake, there are two holes in the lower part, closed with lids.

When operating a powder brake, careful monitoring of its operation is necessary to avoid cases of rotor jamming and powder caking. Due to changes in meteorological conditions during

The brake barrel may become sweaty and the powder may become moist, so before starting work it is necessary to check the powder for moisture and, if necessary, dry it. During periods where dew or frost is likely to occur, it is recommended to remove brake powder. During operation, the powder wears out, and therefore its flowability, magnetic permeability and bulk density decrease. Indicators of powder wear are its color and volumetric mass, therefore, during operation, at least once a month, a sample of the powder is taken and its volumetric mass is measured.

Overall, installation and connection dimensions of the brake are shown in Fig. 25.28.

25.6.3. Electromagnetic brake water-cooled EMT-4500

Electromagnetic brake designed for intense braking when descending drilling tool. The brake is installed on the frame of the drawworks.

Operating mode - S4, duty cycle = 40%. Climatic modification and placement category - VI or T2 according to GOST 15150-69. Group of operating conditions - M18 according to GOST 17516-72.

Brake technical data

Nominal brake momesh, N - m........... 45

Maximum short-term (up to 10 s) torque, Nm. . . .57 - 60

Rated excitation current, A 135

Maximum short-term excitation current, A.....180

Rated excitation voltage, V.........120

Rotation speed, rpm. . . 500

Weight, kg.........6300

The brake sensor is made of 5 rings, each of which has 30 cat-shaped poles. The poles are T-shaped (3 rings) and L-shaped (2 rings). The rings are fastened in such a way that the poles of one ring fit into the groove of the other. Excitation coils are placed between the rings in special grooves. To drain condensate at the bottom of the stator under the coils

excitations are provided with drainage holes.

Rogor - a welded structure in which there are two cylinders, connected to each other with the help of shields. The cavity between the cylinders is divided along the circumference into compartments, in each of which there are input and output cylinders.

On the water distribution side, the shaft has five longitudinal shafts, four concentrically located - inlet and central - outlet. A pipe is built into the center of the channel through which air is supplied to the tire-pneumatic coupling. The cavity formed by the pipe and the shaft channel serves for the passage of cooling water. The shaft channels are connected to hoses that rejected the rotor. There is a roller bearing on the cotton wool. Welded bearing shields. A tachometer is mounted on one of the gates, which is a brake rotor speed sensor.

The principle of the brake action is as follows when applying the brake! When the voltage is applied to the excitation coils, a magnetic flux appears and eddy currents are induced in the massive rotating rotor. Interaction of eddy currents

Rice. 25.29. Overall and installation dimensions of the EMT-4500 brake

The torus with the stator magnetic flux creates a braking torque, and the energy in the brake is converted into heat, for which cooling water is supplied to remove it. The braking torque can be smoothly adjusted by changing the excitation current.

Overall, installation and connection dimensions of the brake are shown in Fig. 25.29.

It is a device (electromagnetic) that is designed to separate and connect two main shafts or a shaft with a part freely sitting on it. The electromagnetic clutch has a very wide range of applications. So, this part is used in diesel locomotives, metal-cutting machines and similar mechanisms. However, at the same time, the couplings used in all these devices and mechanisms are far from the same. So, even the electromagnetic clutch of a gazelle differs from the electromagnetic clutch of a Kamaz.

There are electromagnetic couplings:

• friction electromagnetic clutch (cone, disk);
• gear electromagnetic coupling (they are traditionally located on the end surfaces of the coupling and have small teeth);
• liquid (powder) electromagnetic coupling (the gap in the (magnetic conductive) system between the parts of the coupling is filled with a liquid (powder) mixture with ferrimagnetic powder).

The operating principle of the electromagnetic clutch

Let's consider the general basic principle of operation of an electromagnetic clutch.

A typical clutch consists of two rotors.

One of these rotors is an iron disk with a protrusion (circular and thin) on the periphery. On inner surface This protrusion has pole pieces (radially oriented), which are equipped with windings through which the excitation current is transmitted from the source through special slip rings on the shaft.

The second rotor is also represented by an iron cylindrical shaft with grooves that are located parallel to the axis. Insulated copper bars are inserted into these grooves, which are also connected at the ends by copper collectors. This rotor can rotate freely inside the first one and completely covers it with its pole pieces.

When the excitation current is turned on and one of the rotors, for example, the second, is rotated by the engine, the magnetic field lines (power) are crossed by the conductors of this flux and an electric motion force is induced in them. Due to the fact that the copper bars form a closed circuit, a current flows through them, which generates its own magnetic field. The interaction of the rotor fields is such that the driven rotor is carried along behind the leading one with a slight delay.

Electromagnetic couplings: classification depending on application

Now let's take a closer look at electromagnetic couplings, depending on their area of ​​application:

1. Electromagnetic clutch etm.

This electromagnetic coupling is designed to protect mechanisms and devices from pulse overloads. It also guarantees small idle losses. Taken together, this has a very, very positive effect on the thermal balance of the mechanism, and also facilitates the (fast) start-up of devices even under load.

The couplings under consideration are divided, depending on their design, into the following:

• electromagnetic contact coupling;
• electromagnetic contactless clutch;
• brake electromagnetic clutch.

The compressor electromagnetic clutch is a unit that is installed in front of the compressor and consists of:

• pressure plate;
• pulley (driven by a belt);
• coils (electromagnetic).

This pressure plate is directly connected to the main shaft, while the pulley and reel are mounted on the front cover of the compressor. When power is applied to the coil, it creates a magnetic field that attracts the pressure plate to the pulley, thereby driving the compressor shaft. At the same time, the plate rotates along with the pulley.

The electromagnetic clutch of the air conditioner, when diagnosing its breakdown, often causes a lot of doubts and general confusion. In fact, the causes of the malfunction may be:

• malfunction of the pulley bearings (the bearings must be replaced);
• the clutch itself has “burnt out” (indicates serious internal problems of the compressor and requires in-depth diagnostics);
• malfunction of the pressure plate (the root cause is an incorrectly inserted gap).

3. Electromagnetic fan drive clutch.

This electromagnetic clutch is used in engine cooling systems to maintain thermal regime within certain limits, for example, within 85-90 degrees Celsius.

At the same time, the use of such a coupling allows:

• improve temperature regime engine in winter time with the fan on;
• significantly reduce power losses at the fan drive, thereby significantly reducing fuel consumption.

Depending on the type of energy, couplings are divided into:

— electromagnetic mechanical couplings;

— electromagnetic hydraulic couplings;

— electromagnetic clutches.
At the same time, the most common clutches are also divided into:
1) by type of friction:

— wet (work in oil);

- dry.
2) by switching mode:

- not constantly closed;

- constantly closed.
3) by the number of disks (slave):

— single-disk;

- double-disc;

- multi-disc.
4) by location and type of springs (pressure):

— with a diaphragm central spring;

- with springs located along the periphery of the disk (pressure).
5) according to the control method:

- With mechanical drive;

— with hydraulic drive;

- with combined drive.
5. Electromagnetic clutch em.
These couplings are most often used to control machine tool chains (kinematic).

At the same time, in order to this coupling worked effectively, the following conditions must be observed:

• the environment must be non-explosive, free of aggressive vapors and gases in high concentrations, as well as conductive dust and liquids;
• the place where the coupling will be installed must be reliably protected from emulsion and water;
• The working position of the coupling must be horizontal.