Five practical tips to keep your facilities and business on through potential power outages

Healthcare services, water plants, data centers, greenhouses, food manufacturing and textile facilities all play a key role in our modern, everyday lives. These industries also have another thing in common; uninterrupted access to electricity is critical for the continuity of their operations. 

Fortunately, resiliency and flexibility in our electricity infrastructure is expected to prevent any large-scale blackouts. Moreover, these facilities are also commonly equipped with on-site back-up power generation systems. These systems keep these critical facilities running if the utility power goes out. 

This article outlines five practical maintenance tips for your business' back-up power system. These tips aim to address preventable and inspectable issues, and are complementary to your scheduled and unscheduled maintenance procedures, not substitutes to your existing procedures. 

No. 1: Regularly exercise your back-up power systems 

Regular exercising helps with reliable engine starting. It keeps engine parts lubricated, prevents oxidation of electrical contacts and uses up fuel before it deteriorates. Exercise your generator set at least once a month for a minimum of 30 minutes loaded to no less than one-third of the nameplate rating. Try avoiding periods of no-load operation, since unburned fuel tends to accumulate in the exhaust system. One testing option is to simulate a power outage by conducting the test with your facility's load. Alternatively, you can use a load bank during testing if connecting to the facility load is not convenient for test purposes. 

No. 2: Ensure there is adequate fuel; confirm fuel quality 

Start by checking the main and day tank fuel levels to ensure you have enough fuel to operate as needed. Continue your visual inspection by checking for any leaks, cracks or loose connections. Tighten the clamps as necessary. Inspect the day tank float switch; it ensures the day tank is getting filled from the main fuel tank, as the fuel level within the day tank drops. Drain any water or sediments from the fuel system if necessary. Diesel fuel, when stored, is at risk of contamination. Exercising the generator set regularly is one way to address the contamination risk, since the fuel gets used through this planned exercise. NFPA 110 recommends testing fuel quality at least annually to ensure stored fuel has not degraded significantly and to identify treatment opportunities. If there is need, you can consider fuel polishing and tank cleaning. 

No. 3: Confirm that starting batteries are sufficiently charged  

Weak or undercharged starting batteries are the most common cause of standby power system failures. Begin with a visual inspection of starting batteries. The connections at the terminals need to be tight and clean of any corrosion. You can clean the batteries by wiping them with a damp cloth. Corrosion at the terminals can be cleaned with a solution of baking soda and water. Finish up by checking the electrolyte level and specific gravity. Fill the battery cells with distilled water if electrolyte levels are low. If the specific gravity reading is below 1.215, charge the battery. You can also check whether the batteries have recently been replaced; batteries should be replaced every three years.

No. 4: Regularly inspect and test power system transfer equipment

Transfer switch equipment generally requires limited maintenance, compared to power generators. Start by verifying all indication lamps are functional, and the control switches are in the proper (AUTOMATIC) position. Check circuit breakers and fuses to ensure they are free of dirt or corrosion. If your facility is required to be NFPA 110 compliant, test the transfer switches at least once a month. 

No. 5: Conduct daily visual inspections of your back-up power system

A simple daily walk around your back-up power system could help you identify preventable issues before they lead into loss of life, personal injury, property damage or loss of business income. Conduct a daily visual inspection including, but not limited to:

• Check for oil and coolant levels.
• Check for any debris, loose or broken parts; check if there are any leakages.
• Check the operation of the engine coolant heater(s). If the engine block is not warm to the touch, the jacket water heaters are likely not working and the engine may be challenged to start.
• Keep the area around the generator clear; do not store items around or on top of the generator. 
• Make sure the generator and automatic transfer switches are locked 

Please ensure to follow the schedule in the operator's manual for routine periodic engine and generator maintenance in addition to these practical tips. Many of the tips in this article are adapted from the following resources that you can check for further details.

• Maintenance is one key to diesel generator set reliability
• Cummins Application Engineering T-011: Transfer Switch Application Manual (Requires access to Power Suite, a free, industry leading online tool for power system product sizing and specification generation) 
• Cummins Application Engineering T-030: Liquid-Cooled Generator Set Application Manual (Requires access to Power Suite, a free, industry leading online tool for power system product sizing and specification generation)

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