Chapter 8 — Inspection and Maintenance
Part No. 750-184 8-19
The coupling must be checked for both parallel (offset) alignment and
angular (gap) alignment. Parallel misalignment exists when shaft axis are
parallel but not concentric. Angular misalignment is the reverse situation -
shaft axis concentric, but not parallel.
Checking parallel alignment, both horizontal and vertical can be
accomplished, by laying a straightedge across the coupling halves and
checking with a thickness gauge to obtain the amount of misalignment. The
check should be done on the top of the coupling and at 90 degrees. A useful
hint is to hold a flashlight behind the straightedge so that any gap can readily
be seen.
Shim stock of appropriate thickness and area is then used under either the
feet of the pump or the motor to establish parallel alignment. A tolerance of
.008" is a permissible limit.
After parallel alignment is established, check for angular alignment, which
is done by checking the gap between coupling halves. The coupling should
have a minimum gap of 1/16" and a maximum of 3/32".
Set the spacing between the halves at one point by using a thickness gauge
and then rotate the coupling slowly to be sure that clearance at that point
remains the same through 360 degrees of rotation. Adjust to obtain proper
gap by loosening the hold-down bolts and shifting either the pump or the
motor as required. Generally, a slight tapping on either the front or rear legs
is all that is needed to obtain lateral adjustment. Rear legs may require
shimming for vertical correction.
Tighten the hold-down bolts after adjustments are made and recheck
alignment.
Calipers can also be used to check angular alignment. Measure the overall
distance of the outer ends of the coupling halves at 90° intervals. Shift the
pump or motor, as required, so that the ends of the coupling are the same
distance apart at all points. The coupling will then have proper angular
alignment.
Remember that alignment in one direction may alter alignment in another.
Recheck both angular and parallel alignment procedures after making any
alteration.
A properly aligned coupling will last longer and will provide trouble-free
mechanical operation.
Air Compressor Replacement
Use the following procedures in replacing the pump on a CB-LE. Be sure to
tag the motor leads if disconnected to simplify reconnection.
Dismantling
1. Lift out the two front cylinder pins that hold the screen, and remove the
screen.
2. Disconnect the flared nut on tubing “A” (behind screen) and lift tubing “A”
high enough to prevent drainage of lubricating oil from the tank.
3. Disconnect the flared nut at the orifice fitting.
4. Remove the two sheet metal screws that hold the cylinder in place. One
screw is located at the top rear of cylinder, the other is at the bottom front.
To Next Page
Loading...