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GE Pegasus MHV GEEP-427-I Instuctions page 40

Horizontal induction motor totally enclosed water-to-air cooled sleeve bearing
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End Shield
An end shield is provided on each end of the
frame to support and position the rotor relative to the
stator assembly. The end shields carry the weight of the
rotor and position or center the rotor in the stator
minimizing the unbalanced magnetic forces.
The end shield is machined with a rabbet fit to
mate with shield frame and to mount the bearing
assembly.
Air Deflector
The air deflector is secured with screws to a
vertical frame plate near
circumferentially shrouds the fan and directs the entering
cooling air to the vortex of the fan and prevents the
pressurized air from recirculating back through the fan.
The air deflector is made of glass-fiber, reinforced,
molded thermosetting resins and is split at the horizontal
certerline in order to facilitate assembly and disassembly.
Fig. 2 Prewound stator core
40
GE Energy Motors GEEP-427-I
GEEP-427-I Pegasus, Horizontal Induction Motor
each end of frame. It
TEWAC, Sleeve Bearing
Stator Core and Coils
The stator core and coils (along with the
equivalent
rotor
parts)
electromagnetic parts of the machine. The stator core is
prewound, i.e. the stator coils are wound into the core
prior to installing the core in the frame.
The core is made from segmental laminations
punched from magnetic silicon steel. The punchings are
accurately positioned and stacked to maintain a true
stator bore. The core is build up axially with packets of
punchings separated by radial air ducts.
Stator flanges are located at each end of the stator
core to hold the punchings together in compression. The
interlaminar pressure is maintained by steel straps which
run axially along the outside diameter of the stacked
core, from the annular plate on one end of the core to that
on the other end. These steel straps are welded to the
end plates while the core is under heavy axial
compression.
The stator coils are formed from insulated,
rectangular copper wire. The wire insulation consists of
an enamel, glass, and/or corona-resistant materials. The
wire insulation is over-wrapped with mica tape for
additional surge voltage protection, if necessary. The
formed coils are insulated to ground with mica tape,
which is over-taped with glass tape for physical
protection.
For machines rated 6000 volts and above, a semi-
conducting material is applied to the slot portion of the
coils and graded beyond the core to provide corona
protection.
The coils are wound into the stator core and
wedged into the slots with fiber glass-reinforced wedges.
Bracing is then added to the coil extensions, beyond the
ends of the stator core. The entire prewound stator core is
vacuum-pressure impregnated with epoxy resin and then
cured by baking.
Copyright 2009, The General Electric Company, USA
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