Machine Alignment (Open-Drive Machines); Alignment Methods; Preliminary Alignment; Near Final Alignment - Carrier 17 Start Up & Operation Manual

7. Insert O-ring (Item 12) into packing gland (Item 14).
8. Place contact sleeve (Item 16) face down on clean cloth
or cardboard.
9. Place outer spring (Item 15) over sleeve.
10. Separately assemble seal housing cover (Item 2), pack-
ing gland gasket (Item 13), packing gland (Item 14), and
O-ring (Item 12).
11. Oil the contact sleeve and the O-ring and place the hous-
ing and gland assembly over the sleeve.
12. Carefully depress the spring until snap ring (Item 11)
can be attached to the sleeve.
13. Position key (Item 6) to complete the bench assembly.
14. Install seal housing cover gasket (Item 1) and cover as-
sembly on the compressor.
15. Remove the snap ring.
16. Install shaft-end labyrinth gasket (Item 5) and labyrinth
(Item 7).
17. Install windage baffle (Item 4). Attach snap ring to baffle
for safekeeping.

Machine Alignment (Open-Drive Machines)

ALIGNMENT METHODS — There are several established
procedures for aligning shafts. The dial indicator method is
presented here since it is considered to be one of the most
accurate and reliable. Another faster and easier method for
alignment involves the use of laser alignment tools and com-
puters. Follow the laser tool manufacturer's guidelines when
using the laser technique.
Where job conditions such as close-spaced shafts prohibit
the use of dial indicators for coupling face readings, other
instruments such as a taper gage may be used. The same pro-
cedures described for the dial indicator may be used with the
taper gage.
Shafts placed in perfect alignment in the nonoperating (cold)
condition will always move out of alignment to some extent
as the machine warms to operating temperature. In most cases,
this shaft misalignment is acceptable for the initial run-in
period before hot check and alignment can be made (see Hot
Alignment Check section, page 60.)
NOTE: The physical configuration of the 17FA compressor
makes the oil sump temperature a more significant factor in
alignment than the suction and discharge temperatures. There-
fore, warm the sump oil to operating temperature (approxi-
mately 140 F [60 C]), if possible, before beginning align-
ment procedures.
General
1. Final shaft alignment must be within .002-in. TIR (Total
Indicated Runout) in parallel. Angular alignment must be
within .00033 inches per inch of traverse across the cou-
pling face (or inch of indicator swing diameter) at oper-
ating temperatures. For example, if a bracket-mounted
indicator moves through a 10-in. diameter circle when
measuring angular misalignment, the allowable dial move-
ment will be 10 times .00033 for a total of .0033 inches.
2. Follow the alignment sequence specified in the Near
Final Alignment section.
3. All alignment work is performed on gear and drive equip-
ment. Once the compressor is bolted in a perfectly level
position and is piped to cooler and condenser, it must not
be moved prior to hot check.
4. All alignment checks must be made with equipment hold-
down bolts tightened.
5. In setting dial indicators on zero and when taking read-
ings, both shafts should be tight against their respective
thrust bearings.
6. Space between coupling hub faces must be held to cou-
pling manufacturer's recommendations.
7. Accept only repeatable readings.
Gear and Drive Coupling Alignment
1. Move gear with coupling attached into alignment with
compressor coupling. Adjust jackscrews to reach close
alignment. Follow procedures outlined in Correcting An-
gular Misalignment and Correcting Parallel Misalign-
ment sections.
2. Generally, a 5-in. long spacer hub is supplied between
gear and compressor. Maintain exact hub-to-hub distance
specified on job drawings.
3. Where shaft ends are very close, a taper gage may be used
in place of the dial indicator.
4. Get drive alignment as close as possible by jackscrew
adjustment.
NOTE: Drive shaft end-float at final drive position must not
allow coupling hub faces to contact, or the coupling shroud
to bind.
PRELIMINARY ALIGNMENT — To get within dial indi-
cator range, roughly align the equipment as shown in Fig. 37
and as described below.
Place a straight edge across the OD of one coupling to the
OD of the other. Measure the gap between the straight edge
and the OD of the second coupling with a feeler gage. Then,
by adding or removing shims at each corner, raise or lower
the equipment by the measured amount.
In a similar manner, measure the shaft offset from side to
side and jack the equipment over as required to correct.
70