VARISCO GS Series, Operating And Maintenance Manual

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Pompa ad ingranaggi - Serie GS, GK
Gear pump - GS, GK Series
38
Fig. VI
p) check that the pump axis and the motor are perfectly coaxia
l,
since an offset would
cause aradial force whose strength may reduce the life of the pump or motor (Fig. VII).
Fig. VII
Do not move the pump side coupling; operate on the motor side coupling only.
Leave an axial clearance of approximately 2÷3 mm between the 2 couplings, so as to
avoid stresses induced by axial forces and thermal expansions.
In case of connection by magnetic coupling, proceed as follows:
a), b), c), d) proceed as in the case of the flexible coupling;
verify the coaxiality between the inner magnet cover and the outer magnet cover, by accu-
rately measuring R, difference between the outer cover diameter d and the external outer
magnet diameter D1. This measurement should be made on at least 4 points at 90°; if dif-
ferent values are found in various measurement points, properly place calibrated shims so
as to perfectly align the pump unit;
the non-perfect coaxiality causes differences in the air gap which induce variations of the
magnetic pull force on the inner magnet with consequent radial forces on the shaft and wear
of bushes;
It is also essential to avoid generating axial stress on the inner magnet, which would cause
the consequent premature deterioration of bushes, by leaving the outer magnet free to posi-
tion itself axially. After positioning the pump and the motor, it is therefore necessary to un-
screw the coupling fastening grub screw on the motor shaft and retighten it after the magnet
has moved to its balance position.
Verify that the end of the motor shaft is at a distance of at least 2÷3 mm (axially) from
the inner magnet cover.
It is advisable to mark by two dowel pins the position of the pump on the baseplate, so as to
make the assembly easier after maintenance operations.
When centering the outer magnet, pay particular attention to the effects of the mag-
netic pull force; in particular pay attention to your fingers (always use safety gloves)
and not to damage magnets with accidental shocks.
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