FAQs - Generator Services

Generator service related questions covering sizing for UPS systems and the need for regular service and maintenance.

A generator provides backup power from by converting a fuel source, either diesel or liquid petroleum gas which is stored in a ‘day tank’ typically manufactured to provide 8 hours of runtime at full load. The tank can be refilled either from a remote storage fuel tank or fuel delivery vehicle. If sized properly, a generator could run for longer periods. UPS systems provide backup power from energy stored in their battery sets. The battery set is sized to provide a certain runtime period at a set load kVA or kW. Once depleted the battery set must be recharged. It is normally practice to size a UPS battery set for 10-30minutes where a standby power generator is in place or for longer periods up to several hours if there is no generator. The size and cost of the battery set in comparison to the a standby power generator can rise exponentially the longer the runtime required.

The runtime that a generator can provide power for is a function of the load placed onto the generating set and the size of the tank which is usually measured in litres. Generators are generally sized in kVA or kW and are supplied with an 8-hour, 24-hour (day tank) or 48-hour tank. Check the generator specification for the litres-per-hour consumption rate and capacity of the fuel tank. Our projects team can provide additional bunded tank capacity and a refueling service.

Generators used in critical power applications are generally tested each month as part of a ‘dry-run’ of the entire system. This helps to ensure good lubrication of the internal mechanics and that the generator starter battery is healthy. In terms of maintenance and service contracts we recommend an annual contract with some clients choosing a bi-annual preventative maintenance visit.

If you store diesel for long periods of time in a metal tank it can become contaminated with water, tank corrosion and other matters. Fuel polishing is the process of cleaning the diesel to ensure it is as pure as necessary for powering a generating set. Large diesel generators may have a fuel polishing system installed alongside them to constantly move and filter the diesel. This service can also be provided for other generating sets without an onsite fuel polishing facility.

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