There are several issues to consider when planning for generator resilience in terms of design, operaton and maintenance. Resilience can be improved through parallel generator operation but so will routine maintenance and load bank testing.
Generators are designed to be reliable and to operate in standby mode, power up when called upon, and stand idle most of the time. Reputable manufacturers of top quality generators will put their products through rigorous tests, and run them for up to 1000 hours at standby rating, before leaving the factory. Design elements crucial to reliability include:
- Engine quality – a generator engine should be of a reliable, proven design well suited for the application for which it is intended.
- Cooling system – closed cooling will prevent corrosion; low coolant shutdown will guard against leaks; high coolant temperature shutdown will prevent overheating; UV-resistant hoses will not degrade in ultraviolet light, and top quality block heaters will help starter reliability.
- Corrosion protected terminals are also important, as are dual wire sensors to reduce circuit failure due to unreliable ground return circuits.
- Wiring should be fully enclosed, with waterproof and airtight connectors, coated circuit boards (environmentally sealed from the elements), surge protection, magnetic shielding and fuse protection.
- Generator housing should be painted to bond and protect every seam and edge from potential corrosion. Door hinges, latches, striker plates should all be made from Stainless Steel. Corrosion resistant plated Steel fasteners should be used throughout. Stiffeners on interior walls will provide compartment strength and rigidity.
To optimise generator reliability, gensets should be operated within their design limits and never overloaded, or run for long periods at full power. Nor should they be run for periods of short duration regularly as this will encourage carbon deposits on engine cylinders.
Like any mechanical engine, standby generators require routine and regular service, maintenance and testing in order to achieve optimum reliability. UPS and generators supplied from the same manufacturer will normally be covered by a maintenance plan from the UPS provider. Quite often, AMF (Automatic Mains Failure) panels are capable of remote monitoring by a centralised service centre or over a local network. This will provide valuable information that will assist with both preventative and predictive maintenance and give an early indication of problems. We recommend a combination of preventative and predictive maintenance.
Preventative maintenance typically covers carbon brushes, assemblies and the cleaning of internal components. Predictive maintenance includes vibration analysis, infrared thermography and monitoring electrical conditions. We recommend monthly testing of gensets, under load conditions, or from a load bank, for one hour once a month. Inspection should be made of fuel and oil levels, connections for leaks and spills and attention paid to the starter battery. Generators should receive a full annual service by a qualified and experienced engineer, with consumable items such as filters being replaced at this time.