Holdback
Selection Chart for Holdback Device
- To avoid wear, the nimin speed must not be kept below the stated value. Back stop can also be used as over running clutch while rotating in the reverse direction.
- When using the backstop as over running clutch, the maximum permissible nmax speed, should not be exceeded when transmitting toque, to prevent any damage.
- For stability the stated nimax must not be exceeded.
- For tightening torque for the screw please refer to our installation and maintenance manual.
- Due to our constant endevour for improvement, these data are subject to change.
Advantages
Disengaging speed of the Hold Back need only be protected against corrosion. In case of frequent starts and stops or long slowing down periods oil lubrication should be provided. As a result of designed sprag characteristics the oils with HP or EP additives can be used. In such cases the permissible squareness and concentricity tolerance must be halved.
MOUNTING AND MAINTENANCE
Prior to mounting shaft and mounting flange with spigot have to be cleaned thoroughly. Check if the freewheeling direction is correct. The outer race should be located on its inner diameter only. Bearings must be provided to ensure concentricity of the inner and outer races and support axial and radial loads. Concentricity and runout must be maintained within a limit as shown above. The outer race is fixed to the housing by means bolts of minimum grade of 8.8.
To prevent damage make sure that the drive is not started in backstopping direction. Prior to putting in to operating check if the Hold Back can be easily rotated in the specified over running direction.
If grease is used as a lubricant then over greasing of the Hold Back has to be avoided. In case of oil change the oil initially after 100 operating hours and then every 2000 operating hours. If operational environment is very dirty a more frequent change of oil may be required.
Reversal of overrunning direction is achieved by turning over the cage. Make sure that the cage is not under load while removing. Removal of cage under load is not possible.
SELECTION PROCEDURE
Holdback Selection is based on its ID, OD, Width and Torque Rating. Minimum service factor 2 shall be considered.
Torque = kW x 9550 rpm
kW = Motor Power
rpm = Speed of the gearbox shaft were holdback is to be mounted.