Air Conditioning Compressor Clutch

It is a powerful electromagnet. When the air conditioner is turned on, an electric current flows through the coil turns, forming an electromagnetic field. Under its action, the pressure plate is triggered, which is tightly magnetized to the pulley and starts the compressor.

The main reason for the coil failure is overheating of the part, as a result of which the thermal fuse sealed in the housing is triggered (burns out). To restore the functions, it is necessary to dismantle the faulty coil and install a new part.

The selection of a suitable spare part is carried out according to its dimensions: thickness, outer and inner diameters, as well as the diameter of the seat.

The front (pressure) plate is rigidly fixed to the compressor shaft using a spline or keyed connection. When the air conditioner is turned on, the front plate is magnetized to the compressor pulley and torque is transmitted from the belt to the pulley, from the pulley to the pressure plate, from the pressure plate to the compressor shaft itself.

When the system is turned off, the front plate is demagnetized and the pulley rotates "idle" without transmitting any torque to the shaft.

The front plate can wear out prematurely if the system is faulty and operates at elevated pressure.

The front plate is rigidly fixed to the compressor shaft with a splined or threaded connection. Thus, the rotation from the pulley, driven by the drive belt, is transmitted to the front plate, and from it to the compressor shaft.

The front plate also serves as a compressor fuse; if the load is exceeded, the front plate breaks (tears off) (the cause it calls also breakaway plate), breaking the connection of the pulley with the shaft, and the compressor is switched off, due to which various emergency situations do not affect the air conditioner compressor itself.

The rotation of the compressor pulley in the car air conditioner is ensured by a special bearing. Since the pulley begins to rotate simultaneously with the start of the engine, regardless of whether the air conditioner is on or not, its wear directly depends on the mileage of the car. In accordance with the technical regulations, it is necessary to change the bearing every 100 thousand km, but in our practice there were cases when the bearing "lived" 300,000 and 350,000 km. Its service life depends on the operating conditions: premature wear can be caused by dirt or water getting inside, an overly tight transmission belt, etc.

Car air conditioner bearings belong to the category of non-serviceable parts, therefore, when they fail, the only repair option is replacement.

The selection is carried out only by its dimensions: internal, external diameter and thickness.

When replacing the compressor clutch bearing, it is necessary to use the proper tool to press it out of the pulley and back in. After replacement, it is necessary to crimp the bearing.