GE GEH-5304A - Manual (Page 9)

GEH-5304A
9
Horizontal alignment should be corrected by shifting machines on the base.
b. Alignment Procedure
Flexible Couplings, Self-Supporting Bases
Before operating the machine, the base should be bolted down and the alignment checked as
follows:
1. Remove all of the coupling bolts and slide the shells back so that the hub faces are ex-
posed.
2. Check the coupling hub spacing in accordance with the outline dimensions with the
units in the mechanical center of their end play.
3. Check parallel alignment by using a straightedge across the hubs at both vertical and
horizontal locations or by clamping a dial indicator to one hub and indicating the other
hub on its outside diameter. Be sure that the dial indicator supports do not bend or sag,
since this will give inaccurate readings.
4. Use the dial indicator at hub faces and rotate both units together 90
°
, 180
°
, 270
°
and
360
°
or measure the gap at each position by inserting a feeler gage. The readings should
not vary more than 0.002”.
5. Correct any vertical misalignment by shimming under the units. Horizontal alignment
should be corrected by shifting machine on the base.
2. Grouting
On concrete foundations, a minimum of 1” should be allowed for grouting.
A rich, non-shrink grout should be used. High-grade grout mixtures are available commercially. If
the grout is to be prepared at the site, a cement-sand ratio of 1:2 is recommended. No more than
enough water should be used to give a stiff mixture. The clean but rough surface of the foundations
should be wet and the grout forced or puddled under the base.
3. V-Belt Drives
The V-belt system produces a heavy shaft and bearing loading, making it necessary that these factors
be considered carefully for proper application. Since belt drives impose a bending moment on the
motor shaft, it is always desirable to have the motor sheave located as close to the motor bearing as
possible to minimize both bearing load and shaft stress. This will result in increased bearing life. For
the load centered 2” in toward the bearing from the end of the shaft instead of at the end of the shaft,
the bearing load is reduced by 10% and the life increased by 33%. The bearing life curves that follow
assume the load is centered at the end of the shaft. New improved V-belts are now on the market that
significantly reduce the number and size of belts required for a given load. These new belts should
always be considered, since the sheave will be shorter and the load centered closer to the bearing.
The standard NEMA shaft extension is designed for belted loads. Dimensions are provided on the
standard dimension sheets. A sliding base is available as an accessory to facilitate belt adjustment.
4. Bearing Life
Bearing life for belted drives is determined by calculating the radial load at the end of the shaft.