20
B.
Offset misalignment
OFFSET MISALIGNMENT
COMBINATION OFFSET
AND
ANGULAR MISALIGNMENT
In offset misalignment, the shaft centre lines are parallel but do not intersect.
2.8 Alignment using the Reverse Alignment Method
The following practices are recommended when using the reverse method of alignment. These
should be carried out prior to main alignment.
CHECK FOR SOFT FOOT
This is a check to ensure that there is no undue
stress on the driver holding down bolts; owing
to non-level baseplate or twisting
To check, remove all shims and clean surfaces
and tighten down driver to the baseplate. Set a
dial indicator as shown in sketch and loosen off
the holding down bolt while noting any deflection
reading on the Dial Test Indicator - a maximum
of 0.05 mm (0.002”) is considered acceptable
but any more will have to be corrected by adding
shims, for example, if the Dial Test Indicator
shows the foot
lifting 0.15 mm (0.006") then this is the
thickness of shim to be placed under that foot.
Tighten down and repeat the same procedure
on all other feet until all are within tolerance.
NOTE
If the driver is an electric motor with sleeve bearings then the magnetic centre at which the rotor
will run must be set. This is usually done by lining up a groove in the shaft to a pointer fixed to the
motor body (refer to Motor Manufacture’s instructions).
