Page 582 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

The Post-Shipment Phase: Installation, Pre-Commissioning, Commissioning and Start-up Best Practices Be st Practice 1 0.11
B.P. 10.11. Supporting Material
If you don't know where you started, you do not know where you are
going!
The major machinery components
Think of all the machinery that you have been associated with Fig 10.11.4 Baseline condition
and ask, ‘What are the major components and systems that are
common to all types of rotating equipment?’
Baseline
- Pumps
- Steam turbines
- Compressors Having defined all condition parameters that must be moni-
- Motors tored, the next step in a condition monitoring exercise is to
- Gas turbines obtain baseline information. It is important to obtain this in-
- Fans, etc. formation as soon as is physically possible after start-up of
equipment. However, operations should be consulted to con-
Figure 10.11.1 presents the major component classifications firm when the unit is operating at rated or lined-out conditions.
for any type of machinery. Obtaining baseline information without conferring with opera-
Regardless of the type of machinery, monitor these compo- tions is not suggested since faulty information could be
nents and you will know the total condition of the machine. obtained, which would lead to erroneous conclusions being
drawn for predictive maintenance. Figure 10.11.4 states the
basics of a baseline condition.
Component condition monitoring
It amazes us how many times baseline conditions are ig-
nored. Please remember Figure 10.11.4 and make it a prac-
As previously stated, component and system functions must first tice to obtain baseline conditions as soon as possible after
be defined and the normal values for each component listed. start-up.
These facts are presented in Figure 10.11.2.
Once the function of each component is defined, each major
machinery component can be monitored as shown in Trending
Figure 10.11.3.
Trending is simply the practice of monitoring a parameter
condition with time. Trending begins with baseline condition
and will continue until equipment shutdown. In modern day
- Rotor
- Radial bearing thought, it is often conjectured that trending must be
- Thrust bearing performed by micro-processors and sophisticated control sys-
- Seal tems.Thisisnot necessary!Effectivetrendingcan be obtained
- Auxiliary systems by periodic, manual observation of equipment, or using
equipment available to us in the plant which will include DCS
systems, etc. The important fact is to obtain the baseline and
Figure 10.11.1 Major machinery components and systems
trends of data on a periodic basis. When trending data,
threshold points should also be defined for each parameter that
is trended. This means that when the parameter pre-estab-
lished value is exceeded, action must be taken regarding
problem analysis. Setting threshold values at a standard per-
- Define the function of each affected component
- Define the system in which each affected component operates centage above normal value is recommended. Typically values
- List the normal parameters for each affected component and are on the order of 25e30% above baseline values. However,
system component these values must be defined for each component based on
experience. Figure 10.11.5 presents trending data for a hydro-
dynamic journal bearing. All of the parameters noted in
Fig 10.11.2 Component and system functions
Figure 10.11.5 should be monitored to define the condition of
this journal bearing.

Specific machinery component
- Define each major component
- List condition monitoring parameters and system monitoring parameters
- Obtain baseline data and their limits
- Trend data
- Establish threshold limits
The following sections contain information concerning what
parameters should be monitored for each major machinery
Fig 10.11.3 Component condition monitoring component to determine its condition. In addition, typical limits

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