RWB II ROTARY SCREW COMPRESSOR UNITS
INSTALLATION
S70-210 IOM
Page 7
Figure 1 - Angular Misalignment
COUPLING ALIGNMENT PROCEDURE
The life of the compressor shaft seal and bearings, as well
as the life of the motor bearings, is dependent upon proper
coupling alignment. Couplings may be aligned at the factory
but realignment MUST ALWAYS be done on the job site
after the unit is securely mounted on its foundation. Initial
alignment must be made prior to start-up and rechecked
after a few hours of operation. Final (HOT) field alignment
can only be made when the unit is at operating temperature.
After final (HOT) alignment has been made and found to be
satisfactory for approximately one week, the motor may be
dowelled to maintain alignment.
NOTE: Frick recommends cold aligning the motor .005"
high. This cold misalignment compensates for thermal
growth when the unit is at operating temperature.
The following procedure is applicable to both the CH and
DBZ-B couplings. Dial indicators are to be used to measu-
re the angular and parallel shaft misalignment. Coupling
alignment is attained by alternately measuring angular and
parallel misalignment and repositioning the motor until the
misalignment is within specified tolerances.
ALWAYS LOCK OUT MAIN MOTOR
DISCONNECT BEFORE TOUCHING
MOTOR SHAFT. MISALIGNMENT
MUST NOT EXCEED .004" FOR ALL CH, DBZ-B AND
SERIES 52 COUPLINGS EXCEPT DBZ-B 226 WHICH
SHALL NOT EXCEED .003".
ANGULAR ALIGNMENT
1. To check angular alignment, as shown in Figure 1, attach
dial indicator rigidly to the motor hub. Move indicator stem
so it is in contact with the outside face of compressor hub,
as shown in Figure 2.
NOTE: When DBZ-B couplings are used on motors
with sleeve bearings, it is necessary to secure the two
coupling hubs with a bolt to prevent them from drifting
apart when rotating.
2. Rotate both coupling hubs several revolutions until they
seek their normal axial positions.
Check the dial indicator to be sure that the indicator stem is
slightly loaded so as to allow movement in both directions.
3. Set the dial indicator at zero when viewed at the 12 o’clock
position, as shown in Figure 2.
4. Rotate both coupling hubs together 180° (6 o’clock posi-
tion), as shown in Figure 3. At this position the dial indicator
will show TOTAL angular misalignment.
NOTE: The use of a mirror is helpful in reading the indi-
cator dial as coupling hubs are rotated.
5. Loosen motor anchor bolts and move or shim motor to
correct the angular misalignment.
After adjustments have been made for angular misalignment
retighten anchor bolts to prevent inaccurate readings. Repeat
Steps 3 through 5 to check corrections. Further adjustments
and checks shall be made for angular misalignment until the
total indicator reading is within the specified tolerance.
Figure 2 - Dial Indicator Attached (At 12 O'clock)
Figure 3 - Dial Indicator At 6 O'clock
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