Page 401 - Intro Predictive Maintenance

392 An Introduction to Predictive Maintenance

possible failure modes that could be affecting the blower; however, we still cannot
confirm the specific problem.

17.2.3 Root-Cause Failure Analysis
A visual inspection of the blower indicated that the discharge is horizontal and oppo-
site the measurement point location. By checking the process parameters recorded
concurrent with the vibration measurements, we found that the motor was in a no-
load or run-out condition and that the discharge pressure was abnormally low. In addi-
tion, the visual inspection showed that the blower sits on a cork pad and is not bolted
to the floor. The discharge piping, 24-inch-diameter schedule 40 pipe, was not iso-
lated from the blower and did not have any pipe supports for the first 30 feet of hor-
izontal run. With all of these clues in hand, we concluded that the blower was operating
in a run-out condition (i.e., it was not generating any pressure) and was therefore
unstable. This part of the machine problem was corrected by reducing (i.e., partially
closing) the damper setting and forcing the blower to operate within acceptable aero-
dynamic limits.

After correcting the damper setting, all of the abnormal horizontal readings were
within acceptable limits. The vertical problem with the motor was isolated to improper
installation. The weight of approximately 30 feet of discharge piping compressed the
cork pad under the blower and forced the outboard end of the motor to elevate above
the normal centerline. In this position, the motor became an unsupported beam and
resonated in the same manner as a tuning fork. After isolating the discharge piping
from the blower and providing support, the vertical problem was eliminated.

If you followed the suggested steps in Chapter 5, your predictive maintenance teams
receive training on how to use the predictive maintenance system or systems that were
selected for your program. In addition, they have been exposed to the theory behind
each of the techniques that will be used to employ the data acquired by the systems.
Was it enough to gain maximum benefit from your program?

17.4 ADDITIONAL TRAINING
The initial user’s training and basic theory will not be enough to gain maximum
benefits from a total-plant predictive maintenance program. You will need to continue
the training process throughout the life of the program.

A variety of organizations, including predictive maintenance systems vendors, provide
training programs in all of the predictive maintenance techniques. Caution in select-
ing both the type of course and instructor is strongly recommended. Most of the public
courses are in reality sales presentations. They have little practical value and will not
provide the knowledge base required to gain the maximum benefit from your program.

Practical or application-oriented courses are available that will provide the additional
training required to gain maximum diagnostic benefits from your program. The best