Section 8, Shaft Coupling; Figure 8-1 - Coupling Components - Gardner Denver VST110 Operating And Service Manual

SECTION 8
SHAFT COUPLING
Rotating machinery can cause personal injury or death. Turn the unit
completely off, open the main disconnect, lockout and tagout before servicing
the coupling.
SHAFT COUPLING – Main motors drive their companion compressors by means of curved jaw-type
couplings. Each coupling hub is fixed to the shaft with a setscrew and key combinations. The power is
transmitted through a meshing, single, dry, vibrations damping element – see Figure 8-1, for details of
the main components.
The close-coupled arrangement of motor and compressor, through a machined cast housing, provides
automatic alignment of shafts and coupling. The coupling assembly requires no lubrication.
Coupling Element (Rotex size 65) Inspection and Replacement:
1. Disconnect, lockout and tagout power supply to the compressor package.
2. Remove fasteners securing coupling guard to access opening on compressor-motor housing and
remove guard.
3. Depending on the bore-to-shaft fits (e.g., clearance or interference) on either of the coupling hubs,
proceed as directed. For hub-to-shaft clearance fit hubs:
· Loosen setscrews fastening hubs to shafts and slide hubs away from each other to allow removal
of coupling element.
· Inspect coupling element for signs of wear and tear such as indentations, cracks, deformation,
extrusions, etc. Replace, if necessary.
· After engaging each hub on the matching recesses of the coupling element, check that the gap
between the hub flats (see dimension "E" on Figure 8-2) is no less than 1.38/1.50 inches (35/38
mm). A smaller gap will produce abnormal wear of the element by friction and excessive thermal
expansion – the latter could cause compressor damage by axially displacing the input shaft.
Make sure that keys are in proper alignment with key-ways on hubs.
Figure 8-1 – COUPLING COMPONENTS
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