Alignment And Coupling - GE Custom 8000 Instructions Manual

DLCGEEP-124-I/000, Approved, 2016-11-11, CampinasDM

Alignment and Coupling

General
Machines with antifriction bearings are designed
to have the outer race of the opposite drive end axially
held by the end shield and to allow the outer race of the
other bearing to move axially to allow for the thermal
expansion and contraction of the-rotor relative to the
stator. Because one bearing is held, the machine does
not have any end play designed into the rotor shaft. The
shaft cannot carry any external thrust unless specified at
the design state and designed into the bearing system. A
coupling which allows independent axial movement of
the driven equipment shaft relative to the motor shaft,
such as a splined type (or other axially independent type)
coupling, is recommended for all units with antifriction
bearings.
Parallel and Angular Alignment for
Flexible Couplings
Flexible couplings should not be used to
compensate for inadequate initial alignment of the two
coupling halves. Refer to the instructions supplied by the
flexible coupling manufacturer. Coupling parts, such as
pins, links, buffers, and spacers should be removed
(depending on the type of coupling) and the sleeves
should be axially moved over the shaft to expose the
active hub portions of the coupling halves. The spacing
between coupling hubs should be that recommended by
the coupling manufacturer.
The parallel and angular alignment of the two
coupling halves may be accomplished using the
procedures outlined below, provided the procedures to
not conflict with requirements supplied by the coupling
manufacturer. If a machined, vertical surface is not
accessible on one or both coupling halves, feeler or block
gauges may be substituted for the two dial indicators in
performing the angular alignment check. The two
coupling halves should be aligned to within 0.001-inch
parallel and 0.0015-inch angular misalignment. After
the flexible coupling halves are aligned, the coupling
should be lubricated and assembled in accordance with
the coupling manufacturer's instructions.
GE Industrial Control Systems GEEP-124-I
GEEP-124-I Horizontal Induction Motor
Parallel Alignment for Flexible
Couplings
Position the motor or generator on the foundation
with the plane of its feet horizontal as discussed
previously under Mounting. Axially position the motor
with respect to the machine as discussed in the section
entitled "Installation." Attach a dial indicator on one
coupling hub with the indicating button on the
machined, circumferential surface of the other coupling
hub. See Fig. 1.
Set the dial indicator to zero. Mark the location of
the indicating button with a visible mark. Rotate each of
the two shafts in 90 degree increments, and successively
read and record the dial indications when the indicator
is at 3:00, 6:00, 9:00 and 12:00 o'clock angular
positions. The indicating button must be positioned on
the mark for each reading.
Adjust the shaft position such that the difference
between the two side readings (3:00 and 9:00 o'clock)
and between the top and bottom readings (12:00 and
6:00 o'clock) is less than 0.001-inch. This may require
several iterations. Lateral (3:00 and 9:00 o'clock)
differences are corrected by lateral movement of the unit.
Vertical (12:00 and 6:00 o'clock) differences are
corrected by appropriately adding or removing mounting
shims. The proper shim location is shown on the outline
drawing. Note that the total number of shims in a given
Fig. 1. Arrangement of indicator for parallel alignment
Copyright 1997,1998 The General Electric Company, USA
WPI, Antifriction Bearing
9