RWB II ROTARY SCREW COMPRESSOR UNITS
INSTALLATION
S70-200 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 af-
ter the unit is securely mounted on its foundation. Initial align-
ment 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 fi-
nal (HOT) alignment has been made and found to be satisfac-
tory 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 measure
the angular and parallel shaft misalignment. Coupling align-
ment is attained by alternately measuring angular and paral-
lel misalignment and repositioning the motor until the mis-
alignment 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 cou-
pling 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.
Figure 2 - Dial Indicator Attached (at 12 o'clock)
Figure 3 - Dial Indicator at 6 o'clock
sure that the keys are fully engaged in their keyways. Ensure
that they are reassembled exactly as they were disas-
sembled. Torque disc pack hardware to specification in BP
Series Coupling Data Table.
4. Key and secure the hubs to the shafts by tightening the
clamping bolts. Make sure that the keyways are offset 180°
to maintain balance.
5. Torque the clamping bolts of both hubs to the torque value
given in the Data Table. DO NOT USE ANY LUBRICANT
ON THESE BOLTS.
6. IMPORTANT: Only after the shaft clamping bolts are tight-
ened to their final torque can the keyway setscrew be tight-
ened! If the keyway setscrew is tightened before the shaft
clamping bolts are tightened, then the hub can be cocked on
the shaft.
7. Proceed to Coupling Alignment.
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. Re-
peat Steps 3 through 5 to check corrections. Further adjust-
ments and checks shall be made for angular misalignment
until the total indicator reading is within the specified toler-
ance.
