![background image](http://html1.mh-extra.com/html/gardner-denver/vst225/vst225_installation-operating-and-service-manual_3899650066.webp)
13-17-609 Page 65
8-1
SECTION 8
SHAFT COUPLING
Figure 8-1 – COUPLING COMPONENTS
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 8-2, page 66 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 75) 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
proceeds 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 1.57/1.69 inches (40/43
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.