Well kept maintenance records are invaluable in any maintenance program. They provide the necessary
information for establishing a preventive maintenance and inspection schedule and a spare parts inventory.
The records can also provide some consistency in the program even when personnel turnover is high.
1.2 Predictive Maintenance
Predictive maintenance programs are gaining in popularity in many industries including the power industry.
Maintenance is scheduled based on the analysis of data collected on the condition of the machine or
equipment, not necessarily on any set schedule. To be effective, the machine being monitored has to be
instrumented sufficiently to obtain meaningful data. An automated means of collecting, storing, and
analyzing the data is helpful as well. The most difficult part of a predictive maintenance program is setting
the limits or alarms that indicate when failure is near and maintenance is required. More information and
guidelines are becoming available, but there will always be some fine tuning required for each individual
application. Not all equipment lends itself to predictive maintenance, i.e., it will be more cost effective to
continue with periodic maintenance rather than analyze data to determine the best time for action. A
combination of predictive and preventive maintenance would provide the best maintenance program.
1.3 Inspection Checklists
The information contained in the following chapters is intended to provide general maintenance and
inspection information for some of the most common equipment found in hydroelectric powerplants. This
information, combined with actual operating experience and manufacturer's recommendations, should be
used to develop specific inspection schedules and check lists.
The checklist should be concise, but descriptive enough to leave no question to what information is required
and how it should be obtained. For example, if a bearing temperature is to be checked, indicate where the
thermometer is located and that the reading should be in degrees Fahrenheit or degrees Centigrade. This
should infer to the person performing the inspection that a simple check mark indicating the temperature is
okay is not acceptable. The checklist should also include the range of acceptable values or conditions for
each item on the list. This will allow the person performing the checks to quickly recognize a problem, and
notify maintenance personnel.
II. HYDRAULIC TURBINES, LARGE PUMPS, AND AUXILIARY PUMPS
Basically there are two general classifications of pumps: dynamic and positive displacement. These
classifications are based on the method the pump uses to impart motion and pressure to the fluid.
Dynamic pumps continuously accelerate the fluid within the pump to a velocity much
higher than the velocity at the discharge. The subsequent decrease of the fluid velocity at the discharge
causes a corresponding increase in pressure. The dynamic pump category is made up of centrifugal pumps
and special effect pumps such as eductor and hydraulic ram pumps.