A generator can last for several years to decades but it needs proper maintenance. Just like any other electrical/electronic equipment, generators also need regular maintenance to keep them functioning properly. The quality and frequency of maintenance work determine the life-span and proper working of a generator. Spending time and a little bit of money every now and then on maintenance will further prevent the need for extensive maintenance, buy expensive spare parts and/or replacing the entire unit which will be extremely expensive when compared to the minimal amounts spent on regular maintenance.

Since Diesel Generators are the most widely used from residential to commercial and industrial applications, we will mostly talk about how to maintain your diesel generator or 'gensets'.


Even though diesel generators require a lower standard of care due to their characteristic durability and sturdiness and overall reliability, can withstand heavy power loads and can run for hours (some for unlimited number of hours per year without ever powering down), they still require maintenance on a regular basis to ensure that all the above mentioned qualities last their entire service life.

Maintenance Intervals: Although all maintenance work needs to performed on a regular basis, some types of services need to be performed more frequently than others. The following will list off the type of work that needs to be put in maintenance at these intervals (For all types of Engine-generators):


Weekly Maintenance: Some check-ups need to be performed on a weekly basis such as making sure that there is adequate fuel inside and that there no fluid leakages.Also, every week the generator needs to run at least once (during times when the generator is not being used) and make sure that this test-run (usually with no load connected) concludes without the generator setting off any type of warning lights or sounds or alarms. Also, every week one must check to see if the circuit breaker is functioning properly and is in the closed position and also ensure that the generator is in ‘Auto’ mode for automatic start-up when the power goes out.


Monthly Maintenance: Things like the coolant level, the engine oil level and the state of the battery should be checked every month. Also, every month, the Generator has to be run with the full load connected (auto-transfer switch exercise cycle)


Also, every 6 months, the generator should be serviced by a qualified technician to complete a checklist which includes:
➢    Inspect the enclosure
➢    Check the battery electrolyte level and its specific gravity
➢    Check the battery cables and connections
➢    Inspect the drive belts
➢    Inspect the coolant heater and the coolant lines and connections
➢    Check for oil and fuel leaks and inspect the lubrication system and fuel system hoses and connections
➢    Inspect the exhaust system and the exhaust pipe and the muffler
➢    Check and clean the air intake filter and the air-cleaner unit


●    Scheduled Annual Maintenance ( Also done by a qualified technician): The technician performs a checklist similar to the one performed every 6 months which include:    
➢    Change the oil and the oil filter and the fuel filter and the air filter  
➢    Clean the crankcase breather
➢    Change spark-plugs (if applicable)
➢    Check the coolant concentration and flush the cooling system (as needed)
➢    Perform  Load Banking testing (It is a way of validating the correct operational performance and battery autonomy of the generator system. It tests the generator under load conditions.)
➢    Fuel-testing & reconditioning (diesel units only)
➢    Remove water from the fuel tank (also only for diesel units)
 

A planned maintenance Program for Diesel Engine-generators or Gensets has to be implemented since we all know that preventive maintenance increases the reliability and the life-span of any machine.
As mentioned earlier, it is generally a good idea to establish and adhere to a schedule of maintenance /service based on the application.However, the environment and usage conditions also play a major role in increasing the frequency of check-ups or shortening the aforementioned maintenance schedule A good example of this is if the generator is used for heavy loads for unlimited hours per year in harsh environmental conditions, some of the factors that can require more frequent maintenance include:

• Using the diesel generator set for continuous duty (prime power)

• Extreme ambient temperatures

• Exposure to weather

The Main Aspects Of Preventive Maintenace:
●    General Inspection:
When the generator is in operation, the personnel need to be on the look-out for mechanical problems that could create unsafe conditions.The following components are critical and need to be inspected regularly

• Exhaust system: While the generator is running, the entire exhaust system needs to be checked for any problems. Leaks at all connections, welds, gaskets, and joints need to be repaired immediately. Also, checks should be made to see that the exhaust pipes do not heat up the surrounding area. Excess smoke during start-up can be an indicator of some component failure of the air cleaner or the exhaust system and should be fixed promptly.

• Fuel system: With the generator running, inspect the fuel supply lines, return lines, filters, and fittings for cracks or abrasions.
• DC electrical system: Check the terminals on the starting batteries to ensure they are correctly and tightly connected. Loose or corroded connections create resistance, which can hinder starting.

• Engine: Most engine problems give an early warning. As mentioned in the check-list before, inspect the fluid levels, oil pressure, and coolant temperatures frequently. Prepare for any misfires(engine-backfire), vibrations fluctuating power output or increases in oil or fuel consumption.

• Control system: Inspect the electronic control system regularly to ensure that it is logging data properly during engine runs. As mentioned earlier, after the testing, make sure that the generator is in 'auto' mode.



●    Lubrication service: For accurate readings on the engine’s dipstick, power down and wait approximately 10 minutes to allow the oil in the upper portions of the engine to drain back into the crankcase. Keep the oil level as near as possible to the “full” mark by adding the same quality and brand of oil as specified by the manufacturer. Change the oil and filter at the intervals mentioned before.also, dispose of the used oil and oil filters properly to avoid environmental damage.

●    Cooling system service:Check the coolant level during shutdown periods and if necessary, add coolant until the level is about 3/4 inches below the radiator cap’s lower sealing surface. Heavy-duty diesel engine generators require a coolant which is a balanced mixture of water, antifreeze, and coolant additives. Use the specific coolant type recommended by the generator manufacturer.

●    Fuel system service: Diesel by itself degrades in quality over time.Thus, regular generator set exercise is conducted to use up stored fuel before it degrades. As mentioned earlier, water  accumulates in the fuel tanks of Diesel driven Generators and also must be periodically drained from the tank along with any sediment present.In tropical climates, microorganisms can grow inside of the fuel tanks. This can be rectified by treating stored fuel with a biocide. Regular testing and fuel re-conditioning may be required if the fuel is not used for a few months.
●    Air-intake and air cleaner system: The engine air intake components should be checked as mentioned earlier.The frequency of cleaning or replacing air cleaner filter elements is primarily determined by the conditions under which the generator set operates.
●    Starting batteries: Battery problems are a common cause of generator system failures. Even when kept fully charged, lead-acid starting batteries degrade over time and should be replaced approximately every 2-3 years.

●    Generator set exercise: Generators on continuous standby must be able to go from a cold start to being fully operational in a matter of seconds. This takes a heavy toll on the engine components. However, with routine set excercises, the engine parts are always kept lubricated.Also,it thwarts oxidation of electrical contacts, uses up the diesel before it degrades & in general ensures reliable engine starting. Exercise the generator set every week (without load) and at least once a month(with the load connected) for a minimum of 30 min.  Whenever possible, test the system with actual building loads in order to exercise the automatic transfer switches and to simulate real-world conditions. If this is not possible,conduct the test with at least one-third of the load of the nameplate rating.


Some other ways to maintain your generator directly and indirectly are:
❏    Get/Purchase a warranty on the generator: This is the most sensible thing to do while buying a generator. While the company you buy the generator from will offer warranty and insurance, there are also many third-party companies offer warranty plans for Electrical appliances and for a relatively small amount of money per year you have complete coverage warranty of the several components of your generator.
❏    Keep extra oil and oil filters: The last thing you want to be doing is trying to buy oil or an oil filter during a long power outage. So, keep stock of such supplies like oil and filters and also Heavy Duty Wires and Starter Batteries.
❏    Prevent Burn-outs: Always use heavy-duty insulated cables instead of cheaper and lighter cables. This will prevent premature-motor burn-outs and in the worst case scenario, prevent fires.

Summary: Preventive maintenance for generators plays a crucial role in maximizing the reliability of these backup power systems and reducing the severe financial and life-safety risks associated with the loss of power. Preventive maintenance also minimizes the need for repairs and reduces equipment life cycle costs. By following the aforementioned  maintenance procedures and application-specific manufacturer recommendations, facilities can rest easy knowing that their backup power supply is never compromised