What is an electromagnetic clutch? Application and repair

A coupling is a transmitter of rotating energy from one end of the shaft to the other. This device is in most electric motors for the distribution of mechanical energy. A universal coupling does not exist by design. It can have various forms and design features.

Device

Electromagnetic clutch, like any other, is a combination of the following parts:

• Leading, collecting the motor power;
• Slave, transmitting this power to the regulatory authorities.

If these parts are connected, not displacing, you get a permanently connecting piece.

In the automotive industry, couplings are widely used, the two main parts of which are connected by an electric field and a magnetic field. This makes it possible to connect to the motor without the use of mechanical force, and this also makes it possible to connect in independent positions. Sometimes the electromagnetic clutch allows the regulation of rotational frequencies in the control system.

Types

Couplings are divided as follows:

• The coupling of the driven and leading parts is carried out mechanically;
• The connection between the main parts is carried out by induction. Such a connection is possible due to the magnetic field.

To mechanical carry:

• Frictional. The main parts of this coupling are held together by electromagnetic forces. They can be executed with a different number of disks, and also have a different friction surface (conical or cylindrical shape);
• Powder. In these designs, the driven with the leading part is connected by a special ferromagnetic powder, which fills the space between the components of the mechanism. This powder is magnetized and tightly fastens the parts;
• Dentate (another name - "cam"). Under the action of an electromagnet, the main two parts are held together by denticles located on them.

Induction refers to:

• Asynchronous. In this mechanism, due to the rotational movements of the driving part, an electromagnetic effect is created in the part of the driven part. This part is also called the clutch slip;
• Synchronous. Due to the action of permanent magnets at different ends of this part, under the influence of the current flowing through the coil, a field appears that binds both its parts;
• Hysteresis coupling. As the name implies, the binding of parts occurs as a phenomenon of hysteresis, when the magnetically solid body is remagnetized.

Any of their above principles of operation does not change the main purpose of the coupling: the conversion of the input of mechanical energy into it at the output.

For control and automatic systems, all types of couplings can be used .

The work of induction elements corresponds to the work of an electric motor. Therefore, the most widespread are the following devices:

• Ferro-powder with electromagnetic control;
• Electromagnetic friction clutches.

Ferro-Powder with Electromagnetic Control

With such a part, it is possible to connect the parts both rigidly and with the slip of the driven from the drive. Due to this, it is possible to adjust the speed of the drive mechanism without interfering with the very speed of the drive motor.

The construction of the element is as follows. Both parts of the coupling are steel cylinders, which are magnetic cores. In the driven part there is a groove to which the excitation winding is supplied. It, in turn, is connected to a power source by means of contact rings together with a brush. The space between the parts is filled with a ferromagnetic mixture. It can be powdery or liquid.

Principle of operation

When a DC voltage is applied to the winding, a current is generated that forms an exciting current. It passes through a ferromagnet and magnetizes the latter, its particles are created by magnetized chains. Chains are arranged in the direction of the magnetic field and its lines of force. The resulting force of attraction from the chains and secures the parts of the coupling. The clamping force depends on the magnitude of the current that flows through the chains. With an increase in the effect of the current, the material becomes oversaturated, the coupling force decreases, thus it is possible to create a slip element.

Frictional

When there is a closure of the force in the mechanical connection, then the part can be called a friction clutch or a friction clutch. To connect such a part is possible with engines, which are activated under heavy load. Structurally, these elements can be made from one or more disks with a different friction surface design: in the form of a cylinder or a cone.

Principle of operation

The surfaces subject to friction are connected by an electromagnetic field. Adjust the torque of such a friction clutch is not, it's permanent. Change under the influence of a change in the value of the current it is not subject to. To increase the power this clutch can with a factor of more than 30.

Electromagnetic elements have a subdivision depending on the field of their application.

Electromagnetic coupling ETM

Protect devices and various mechanisms from the overload of impulse only this part is capable. It reduces the loss of idling. This complexly increases the probability of starting the engine, even with increased loads. The electromagnetic clutch is divided into the following:

• Non-contact;
• Contact;
• Braking.

A / C compressor clutch

In the front of the compressor is installed it. It consists of the basic elements: a plate, a pulley, an electromagnetic coil.

The plate is attached directly to the shaft, and the coil and the pulley are located on the front cover. When the power supply that creates the magnetic field begins, the plate is attracted to the pulley and the compressor shaft starts to move. The pulley rotates together with the plate.

If the electromagnetic clutch is broken, it can be repaired by yourself. For successful repair, the cause of the malfunction must be correctly diagnosed. If the compressor clutch breaks, a burnt smell can be felt and noise can be heard. Usually a knock occurs when you need to replace the bearing. There are such malfunctions, which only the master can diagnose if there is special equipment.

If the question arose about replacing such a detail as an electromagnetic coupling ("GAZelle" is not an exception), then problems with finding the necessary equipment should not arise. Well, if the breakdown was discovered on time. This will avoid additional costs when other, associated engine parts fail.
Couplings for different equipment are also different, and in order to avoid mistakes in self-purchase, you can contact the service center.

If the electromagnetic clutches of the compressor fail, the reasons for this may be the following:

• Breakage of the clamping plate when it is incorrectly inserted into the gap;
• The coupling is completely faulty, it can "burn out" and the diagnosis of the cause of this is very complicated;
• Pulley bearings require replacement.

The electromagnetic fan clutch is used to cool the car compressors or to maintain a certain engine temperature.

It is also used to maintain the temperature during the cold season, especially if the fan is turned on. It helps reduce fuel consumption by reducing the power on the fan drive.