Technical inspections of power generators designed for emergency operation guarantee more than 96% efficiency of the device

Emergency power systems based on diesel-powered generator sets, or simply power generators, are installed in facilities where the loss of power mains would pose a threat to work or even to people’s lives or safety.

Operating characteristics of the power generators

Emergency generators are typically configured to start automatically after a power grid failure and provide the facility’s basic energy needs until grid power is restored. Although generators in areas with extremely poor power quality are capable of operating for up to 200 hours or more a year, in regions where power problems do not exist, these machines may not work at all. This is a significant departure from the continuous duty applications for which the motors in these units are typically designed. This variability in operational demand also creates challenges in determining the optimal maintenance and testing frequency for emergency devices with high-reliability requirements.
Periodicity of maintenance has a significant impact on the reliability of a power generator.
It is worth noting that by the general term “maintenance” I mean a combination of preventive maintenance (i.e., maintenance performed at regular intervals to reduce the failure rate), visual inspection and stress testing. A typical maintenance plan ranges from very simple items at set intervals, such as visual checks (e.g., to make sure vents and shutters are not blocked, check operating fluid levels, etc.), to more crucial items at longer intervals, such as replacing coolant or batteries. An important aspect of the annual maintenance plan is routine testing of the power generator.

Testing power generators

No-stress testing of a power generator involves starting the device, leaving it idling for a short time (usually 15 to 60 minutes), and then shutting it off. This checks the starting system, motor and some control system components, but this method does not stress the motor and does not test the transfer switch. No-stress tests pose little risk to the user, as test failure has a minor direct impact on the ongoing operation of the facility. Such a test is often conducted at weekly or biweekly intervals. Although manufacturers recommend weekly no-stress tests as one of the elements of proper operation, it is worth knowing that motor operation at low loads and low operating temperatures can result in the accumulation of unburned diesel fuel in the exhaust stack, high moisture content in the lubricating oil and other undesirable effects.
Stress testing of emergency generators involves starting the unit and using a load bank to simulate the load. Stress testing guarantees a more accurate performance test than a no-stress test with similarly low risk, but does not check or test the power switch.
The use of a load bank is often the most practical way to test a power generator. Eneria CAT recommends routine testing under an external load (using a load bank) especially when building loads at the generator’s site are low or unusable.
Building load tests of a generator include starting the device and transferring the facility’s load to an operating unit.
Eneria CAT, as an authorised representative of the manufacturer in Poland, recommends that all generators subjected to regular no-stress testing be tested under load, even if not required by law.
The typical load of a power generator set during normal operation should be maintained above 10% of the rated load for the newest units and above 30% of the rated load for older units (it is important to avoid damage caused by low-load operation).
The goal of a properly implemented and designed maintenance plan depending on the type of power generator is the reliability of the device. This is especially important for critical power systems (e.g., Ministry of Defence facilities, banks, server rooms), where cost is a secondary concern, and for facilities where the cost of maintenance is small compared to the financial impact of power loss (shopping malls, server rooms, office buildings).

Maintenance plans

Inspections and checks do not limit the generator’s ability to start automatically, and even if units are shut down for worker safety while inspecting, for example, V-belts or replacing filters, service technicians are available to bring units back to operating condition immediately. As a result, response and repair times will be shorter for failures detected during testing, as technicians are on-site and able to begin corrective actions immediately.
The fact is that diesel generators operating in emergency standby mode, with even a basic level of maintenance (limited to an annual inspection, and a visual inspection performed once every six months), have a much higher operational reliability than equipment without a maintenance plan.
It has also been proven that common commercial maintenance plans (including those involving the user’s technical services) with weekly no-stress generator tests and monthly, bi-monthly or quarterly maintenance achieve an average annual reliability level higher than 96% for well-known units with typical operating hours. In addition, it should be demonstrated that locations with full-time professional staff and very intensive maintenance schedules can reduce the operational failure rate by another 66-80%, reaching a record-breaking rate of more than 99% annual operational availability for similar power generators.
Interestingly, new power generator sets are statistically less reliable than generator sets that have been in use for ten or more years. Power generators are expected to become more reliable as they age. This does not mean that generator sets should remain in operation indefinitely. Over time, the availability of spare parts decreases, and the repair itself carried out by qualified maintenance personnel will take longer than in the case of new generator sets. Nevertheless, exemplary use of the unit (including the use of a maintenance plan in accordance with the recommendations of the Eneria CAT service) will result in the long-term, reliable and trouble-free use of the generator set.

Service life of power generators

When it comes to extending the service life of generators with short total operating hours, potential replacement of the unit or obsolete auxiliary components may be the most optimal solution for some ageing equipment. This is especially the case with changing emission requirements or other local requirements.
It is not uncommon for equipment owners to postpone preventive maintenance, deeming it too costly or time-consuming. However, this is often counterproductive. The cost of business operations related equipment failure during operation is often much higher and requires major emergency repairs. As a result, any savings from ignoring or delaying preventive maintenance quickly disappear.
Equipment failures can also increase the risk of incidents related to occupational health and safety issues. Maintenance plans are an important part of the Eneria CAT service because they support the continued operation of the power generator at the location of its installation, while also ensuring the safety of employees.
Eneria CAT recommends that clients follow CAT® generator maintenance programmes in accordance with the highest standards designed specifically for the type of equipment and covering all critical features and functions of CAT® generators, including:

• changing oil and fluids by using genuine and clean fluids in the engine, hydraulic circuits and cooling system to reduce wear and ensure that the system operates at optimal temperatures, pressures and lubrication levels;

• verifying and servicing electrical systems of a power generator including replacement of bulbs or diodes and fuses, repair of loose or broken wires and installation of a new battery. Electrical failures can be difficult to diagnose, so preventive maintenance can help avoid much more costly failures.

Advantages of preventive maintenance plans

Creating a maintenance plan may seem time-consuming, but the experience Eneria CAT offers helps avoid unnecessary expenses. Eneria has standard preventive maintenance procedures for each type of CAT® power generator.
The best way to detect potential problems with a generator is to perform regular visual inspections (known as A.T. inspection) and scheduled preventive maintenance (A.T.M., V.T.C. inspection). With Eneria CAT’s maintenance plans, service experts regularly inspect the equipment (through visual inspections and technical analysis, such as fluid test samples) and perform a range of activities for preventive maintenance (A.T.M. annual inspection, V.T.C. triennial inspection, stress tests).
The maintenance plan allows you to entrust the responsibility of equipment maintenance to Eneria CAT’s highly trained technicians, giving you confidence in the performance and reliability of the power generator.

Responsible fluid prevention: greater safety

Proper fluid maintenance is essential for equipment and engines to operate at peak performance. Scheduled Oil Sampling (S.O.S.) followed by detailed fluid analysis by Eneria CAT provides a reliable means for early detection of potential problem areas. By monitoring the unit throughout its life cycle, S.O.S. fluid analysis helps identify minor problems before they escalate into major repairs, thereby optimising performance, maximising productivity, protecting valuable equipment, reducing operating costs and increasing the unit’s eventual resale value. Read more about proper oil sampling in our S.O.S. leaflet.
Using state-of-the-art and highly sophisticated analytical technology, Caterpillar’s experienced technicians test oil samples collected at regular intervals. This provides the client with a clear, concise and up-to-date report with accurate interpretations and precise recommendations. The fluid analysis provided by Eneria CAT is one of the most important service support programmes available to equipment owners because early detection of a problem means it can be fixed before it becomes a major failure.

Timely inspections save money

With regular inspection and preventive maintenance, minor problems can be detected before they become major repairs. This allows equipment owners to schedule repairs at a time that is convenient for them, thus increasing safety and ensuring continuity of work.

It is worth remembering that a well-maintained power generator with a good record of service and repairs also tends to have a higher commercial value.

As a rule, the emergency generator is used occasionally, since its primary purpose is to guarantee operation in an emergency situation. Therefore, maintenance of the emergency generator is particularly important because:

• The generator must always be in perfect working condition
• The generator must always be ready to work under load at all times

Scheduled regular preventive maintenance:

• extends maximum availability of the generator for emergency operation
• ensures the longer service life of the generator
• reduced the incidence of costly repairs

The best way to ensure a long engine life is to provide it with preventive maintenance and use only genuine CAT parts^®.

CAT^® power generator works better when equipped with only genuine CAT^® parts, and with filters from this company. CAT^® filters can extend the life of an injector by up to 45%, and reduce the hourly cost of the unit by 400% compared to competing filters. Read more about the uniqueness of CAT^® filters.

CAT^® power generator’s engine is designed to operate as a system/set. Due to this fact, the use of genuine CAT^® parts ensures that the generator system/set operates more efficiently and cost-effectively.

CAT^® batteries, in turn, provide reliability at every startup even in the most adverse and extreme conditions. They are manufactured to provide reliable starting (with cold starting CCA currents and power reserves) and vibration resistance much higher than other batteries. CAT^®batteries can withstand a 100-hour vibration test while competing batteries last only 18 or 36 hours.

Adequate protection for the CAT^® power generator is also provided by the CAT^®coolant with extended shelf life. Thanks to advanced technology, it protects the cooling system from corrosion and deposit formation like no other brand, while extending engine life and fluid replacement frequency.

FUEL CONSUMPTION

• Fuel costs amount to 40% of total operating costs;
• Contaminated fuel may cause problems with injectors, which can use up to 12% more fuel;
• Fuel savings from proper maintenance can reduce operating costs by 5-10%;
• Therefore, it makes sense to invest in the best CAT^® filters on the market as the investment will pay off, for example, in lower fuel consumption.

OIL CONSUMPTION

When oil consumption increases 3x, an engine overhaul is needed.

Implementing a well-managed maintenance plan will contribute to:

• Minimising downtime
• Reducing engine operating costs
• Increasing engine service life

Lack of a maintenance plan will result in:

• Additional costs of related damages, caused by failure
• Costs of the extra work involved in repairing the failure and related damage and cleaning the engine
• Costs of (unplanned) downtime and loss of productivity while repairs are being performed
• The cost of additional used or damaged parts that could otherwise be reused. Read more…

Written by: Zofia Rzeźniczak

Parts & Service Sales Representative/Diesel Market