Check torque transmission

Especially if a motor other than the one suggested in the Bitzer Software is used, make sure that the torque transmission between the motor shaft and the coupling half in contact is sufficient. This is the case if the length of the torque transmission (i.e. the length that the motor shaft and the coupling are adjacent) is equal to or greater than the diameter of the motor shaft (cf. dimensional drawing of the respective coupling).

Observe distances between shafts and between coupling halves!

Observe distances between shafts and between coupling halves!

The distance between the two shafts must be at least 5 mm to prevent contact, e.g. during heating.
The distance between the coupling halves, on the other hand, must be 2 .. 5 mm.

Example of suitable combination of coupling, coupling housing, motor and compressor:

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This coupling fits both the compressor and the motor: The length of the torque transmission for both shafts is equal to or greater than the diameter of the respective shaft. (Shown here to scale, but without specific dimensions. These are listed with the respective coupling).

Coupling may be moved

With short motor shafts, unfavourable coupling housings, etc., the torque transmission may not be sufficient for one of the two shafts – often for the motor shaft. In this case, it is often possible to shift the coupling slightly in the direction of the motor until the length of the torque transmission is sufficient. However, it should be noted that the torque transmission from the coupling to the compressor shaft must also remain sufficient.

Example of an initially not matching combination:

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The coupling does not initially fit the compressor and motor (above): The length of the torque transmission of the motor shaft is less than the diameter of the motor shaft. In this case, the coupling can be moved slightly towards the motor so that the torque transmission is adequate again – without the torque transmission on the compressor shaft now becoming too short. (Shown here to scale, but without concrete dimensions. These are listed with the respective coupling).

For OS.A95 and OS.A105 compressors, couplings with different hub lengths on the motor side are available to suit these cases (dimension "E" in dimensional drawings).

If in doubt, please consult Bitzer.