SG Transmission > Technical Information > Maintenance

SG Transmission Clutches and Brakes are robustly designed and are virtually maintenance free. However, in cases where they are used to control relatively large inertia loads or high switching frequencies are employed, they may periodically require the air-gap checking and adjusting. Where necessary, these air-gaps should be reset in accordance with the dimension ‘g’ in the dimensional information section of this manual. The period between adjustment is governed by the application and will differ depending upon your specific requirements.

Clutch Type 51: styles FM, S.B., and B.B. can be adjusted by the removal of the correct number of shims between clutch rotor and armature hub.
Split shaft arrangements using C.C style armature assemblies may only require the locking screw in the hub boss loosening and the hub sliding along the shaft until required dimension is obtained.

i) With clutch coil de-energised measure the air-gap, in three places, between the clutch face and armature plate using feeler gauges.

ii) If the air-gap exceeds the dimension ‘g’ by more than 0.20mm then some adjustment may be necessary.

iii) Remove the armature assembly from the shaft and measure / remove the required number of shims to obtain the given dimension.

iv) Examine the clutch rotor face and armature face for evidence of oil/grease, if the surfaces are contaminated consult the “Operating Problems - Contamination” section of this manual.

v) If the surfaces appear acceptable then re-fit the armature assembly and re-check the air-gap.

vi) Operate the unit and check it is functioning correctly.

Brake Type 52: the air gap will be set either by shims or by locking the armature assembly in position on the shaft. The procedure for adjustment is practically the same as for clutches.

Clutch/Brake Modules Type 54: check the air-gap at the clutch and brake as above. The size 03 module uses shims but on larger sizes adjustment is achieved using the locknuts that hold the armature assemblies onto the shaft.

i) Secure the shaft to prevent it rotating during adjustment. Unlock the clutch adjusting nut (tab washer or locking screw depending upon size) and rotate it to move the armature assembly along the shaft until the air-gap is correct.

ii) Repeat this procedure for the brake.

iii) Energise and de-energise the clutch and brake several times to settle the components in place. Recheck the air-gaps and if necessary repeat the steps above.

iv) Lock the adjusting nuts using the tab washers or locking screws.

Clutch/Brake Modules Type 55:

i) Remove the inspection plug from the housing and energise the bake (output) coil.

ii) Measure the gap between the clutch face and the armature with feeler gauges.

iii) If the gap exceeds the value “g” by more than 0.2 mm, adjusting shims should be removed from the housing. Plastic shims are colour coded: amber 0.1 mm and blue 0.2 mm. Steel shims are 0.2 mm thick.

iv) To remove the housing shims, slacken the bolts that hold the output bearing housing in place. The shims are semi-circular and can be pulled out with pliers from either side of the module. Note that the shims are in pairs and the same number of shims must be removed from each side.

v) Tighten the housing screws ensuring that the shims are properly located.

vi) Re-check the air-gap and, if correct, re-fit the inspection plug.

Clutch/Brake Modules Type 56:

Generally supplied 'Pre-set' without the need to set air gap prior or during installation.

Power Off Brakes Type 62: energise the brake to release the armature so that the air-gap can be measured. The air gap is then adjusted in the same way as for a type 52 brake.