GE Pegasus MHV GEEP-427-I Instuctions page 19

7. Observe the temperature of windings
(Resistance Temperature Detectors (RTD's) are
provided on all machines). In no case should the
windings exceed the sum of the rated rise on the
nameplate plus the maximum design ambient.
8. Determine that the amplitude of vibration
is not excessive (see the section entitled "Vibration"
in this publication). Misalignment should be the first
item to check if there is unacceptable vibration.
9. Verify that all accessories supplied with
the machine are functioning normally and are
performing consistent with the load on the machine
and system.
10. Verify that all control and protective
devices are functioning normally and are performing
consistent with the load on the machine and system.
11. The machine should be operated and
fully observed for not less than two hours and should
be free of any problems before it is released for
normal duty.
12. As stated earlier, the machine must be
shut down immediately if any problem occurs.
Should any problem occur, it source should be
determined and corrected, and then the initial test run
should be repeated.
Vibration
General Electric motors and generators,
covered by this Instruction Manual, are balanced at
the factory, in accordance with NEMA Standard MG
1-20.52 and MG 1-20.53, to be within the following
limits (unless otherwise specified in the sales
contract).
Table 1 – Bearing Housing Unfiltered Vibration
Limits
Speed
(rpm)
3600
1800
1200
900
720
600
GE Energy Motors GEEP-427-I
Velocity
(inches/sec peak)
0.12
0.12
0.12
0.12
0.072
0.064
GEEP-427-I Pegasus, Horizontal Induction Motor
Vibration amplitude measurements are made on the
bearing housing and are taken in the vertical, horizontal and
axial directions.
Table 2 - Limits for the unfiltered maximum relative
shaft displacement.
Speed
(rpm)
1801 - 3600
< 1800
If the owner's half coupling was sent to the factory
to be mounted onto the machine shaft extension, the rotor is
balanced with the half coupling installed. Otherwise, the
rotor is balanced with a half key (i.e., the keyway is filled
with a steel bar equal in length to the key length shown on
the outline and flush with the top of the keyway). The shaft
key furnished with the machines of 1500 rpm and higher is a
full-length, full key with a three-inch long half key extension
on one end. To maintain factory balance, cut the key to
length as follows. See Fig. 5.
1. Measure the coupling hub length (H) and cut the
full key to length H by cutting the excess from the
full key end.
2. Cut the half key end so that the overall key length
equals the key length shown on the outline drawing.
3. Full key must fill coupling/keyway. Half key must
fill shaft/keyway.
WARNING: TO AVOID EXCESSIVE STRESSES IN
THE KEY, THE MAXIMUM LENGTH OF THE
HALF KEY SHOULD NOT EXCEED 3.0 INCHES.
FAILURE TO OBSERVE THIS PRECAUTION MAY
RESULT IN DAMAGE TO THE EQUIPMENT,
INJURY TO PERSONNEL, OR BOTH.
The
accordance with the requirements in the section entitled
"Foundation" on page 7. If the unit has been properly
aligned, the amplitude of the vibration of the installed motor
should be as stated in the above table.
amplitudes are significantly greater than these values, the
instruction referenced
Misalignment is the most probable cause of excessive
vibration. Other possible causes are "soft" shim packs under
one or more feet, loose foot bolts or an inadequate
foundation. Contributions to vibration from the driven
equipment should not be overlooked.
Copyright 2009, The General Electric Company, USA 19
TEWAC, Sleeve Bearing
Maximum Relative Shaft
Displacement (inches peak-to-peak)
0.0028
0.0035
foundation should be
above should
constructed in
If vibration
be reviewed.