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Series WD-L  
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Series Overview


        Maximum torque Md max of individual sizes

Limiting load diagrams of individual sizes for “compressive” load
Please refer to the explanations in the Technical Information section of the catalog

Due to the high gear ratio and the large surface contact between worm and worm gear, very high torque values can be transmitted using very small sized Slew Drives (highest power density). Worm gear driven Slew Drives of the light series WD-L are short-cycle drives for rotation and swiveling applications . Use in continuous rotation applications is not permissible due to higher duty. The duty should be selected so that over-heating around the gearing contact cannot occur. Diagram 2 exhibits the maximum permissible duty per minute, depending upon operation torque. When this maximum permissible duty per minute EDmax ’ is exceeded, the permissibility must be checked by the IMO Engineering Department.

The following conditions apply when determining the maximum permissible duty per minute and when verifying the wear characteristic of worm gearing:

  • Output speed: n = 1.0 rpm
  • Wear safety factor of worm gearing: SW = 1.3
  • Observance of the maximum permissible duty EDmax ‘ (see diagram 2)
  • Ambient temperature 20°C

Determining the maximum permissible duty per minute EDmax ‘ :
The maximum permissible duty per minute should never be exceeded

EDmax ': Maximum permissible duty per minute in percent per minute [% / min] (see diagram 2)

fMd:     Ratio of operating torque to maximum torque [-]
Md B:     Operating torque [Nm]
Md max:     Maximum torque [Nm] (see diagram 1)

Diagram 2

Wear characteristics of the worm gearing:

Gw: Limit value [h] (see diagram 3)
Bh: Operation time [h]
EDB: Duty in operation [%]
Md B: Operating torque [Nm]

The operation is permissible as regards wear characteristics, if the following relationship prevails:

If this relationship is not fulfilled, a high rate of wear must be expected.

Diagram 3

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Slewing Rings
Slew Drives


Slewing Rings
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