Installation instructions

GEI-M1011A
C. Alignment of Solid Shaft Motors
Accurate mechanical lineup is essential for successful
operation. Mechanical vibration and roughness when the
motor is running may indicate poor alignment. In general,
lineup by straight edge across, and feeler gages between
coupling halves is not sufficiently accurate. It is
recommended that the lineup be checked with dial
indicators. The space between coupling hubs should be
maintained as recommended by the coupling manufacturer.
D. Couplings for Hollow Shaft Motors
1. General
Vertical hollow-shaft motors are designed for driving deep-
well, turbine type pumps and can be equipped with either
self-release, bolted, or non-reverse couplings as described in
the following sections. These couplings are located at the
top of the motor and allow pump impeller position to be
adjusted easily. The type of coupling is specified by the
customer. Remove the top cover and fan casing for access
to the coupling
Two slots are provided in the outside rim of the coupling
so that a bar can be inserted to keep the assembly from
turning while the adjustment of pump impeller clearance is
being made. The motor fan must be removed for access to
these holes, but fan removal is a normal step during motor
installation since it is mounted on the upper half-coupling.
A coupling bolt can be screwed into one of the extra
tapped holes in the top end shield to provide a stop for the
bar.
To prevent breakage, coupling bolts must be tightened to
torque values indicated below for bolted or non-reverse
couplings.
Required Bolt Torques
Bolt Size (In.) Torque
1/4
15 N
•m (10 lb-ft)
5/16
25 N
•m (20 b-ft)
3/8
50 N
•m (37 lb-ft)
1/2
120 N
•m (90 lb-ft)
5/8
240 N
•m (180 lb-ft)
3/4
430 N
•m (320 lb-ft)
1
960 N
•m (710 lb-ft)
Note: 1 in. = 25.4 mm
CAUTION: It shall be the installer’s
responsibility in all cases to
ascertain that these torque values
are used and maintained. This shall
include those instances when the coupling
comes mounted in the motor. Failure to comply
may cause the coupling blots to break with
resultant extensive damage to the equipment.
2. Self-Release Couplings
Should the motor accidentally be run in the reverse
direction, the pump line-shaft joints may unscrew. The
self-release coupling acts to limit the amount of this
unscrewing. In normal operation, torque from the motor is
transmitted by the lower half-coupling through the driving
pins to the upper half-coupling, and then to the pump shaft.
If reversal occurs and the pump shaft starts to unscrew and
lengthen, the up per half of the self-release coupling is
lifted off of the driving pins, thus uncoupling the pump
from the motor. See Figures 4-6, where a self-release
coupling is shown to the left of the shaft centerline.
NOTE: Self-release couplings cannot
carry up-thrust.
To install a motor with a self-release coupling, first lift off
the upper half-coupling and the fan attached to it, and
remove the fan from the coupling. Then lower the motor
onto the pump with pump shaft through motor shaft. Next,
set the upper half-coupling into place on the lower half-
coupling and put the gib key in place. Then put the pump
shaft nut in place, adjust the pump and lock the nut.
Finally, set the fan on top of the upper half-coupling and
secure it with its 3 cap screws.
Proper functioning of a self-release coupling depends upon
several factors. The pump shaft adjusting nut must be
securely attached to the top half-coupling, and the top half-
coupling must not bind on the lower half. Otherwise, the
adjusting nut lock-screw may break instead of the coupling
halves separating. Should this happen, the motor would
continue to unscrew. Serious damage to both motor and
line shaft may result. Clearance between the coupling
halves should be checked by placing the top half-coupling
in position prior to installing the motor. It should drop into
place, and rest solidly on the lower half-coupling, without
forcing.
Proper alignment of the pump head shaft within the motor
hollow shaft is also important. After the coupling releases,
it no longer holds the pump shaft centered. If the alignment
is not good, the motor shaft which is still rotating may rub
the pump shaft which has stopped, and damage will result.
A third requirement is that the distance between the top of
the pump shaft and the inside of the top cap be at least
enough to allow the top half-coupling, when it tries to
release, to clear the pins before the shaft hits the cap.
Check this clearance after the adjusting nut has been drawn
up to its final position. To facilitate making the check, the
motor outline print shows a maximum dimension “XH”
from the top of the coupling to the top of the pump shaft.
Adhering to this design limit will allow the shaft and
coupling to lift enough to clear the pins and still leave a
small clearance between the shaft and cap. For standard
motors, “XH” is as shown in Table 1.
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