How to size generators

size generatorsWhen thinking about how to size generators, the most important thing to remember is that your generator size must exceed your UPS power rating. This is because generators need to support both the UPS power rating and an additional 20%-30% to cover the ‘power conditioning’ process.

Harmonics

You will also need to consider harmonics – a distortion of the smooth wave-form of the AC electrical supply. Failure to look at the harmonics within your system can lead to electrical components heating up, which can reduce their lifespan.

Synchronisation

If the generator is working close to full capacity, there is a chance that the generator will drop the load. To avoid this you need to increase the size of your generator to allow for synchronisation with the electrical current supplied by the UPS.

Temperature

When the generator is running, it’s typical for the temperature in the plant room to rise by 10°C. Add this to the ambient temperature, and the generator is running in 30°C heat. To overcome this, you’ll need a larger generator with adequate capacity.

Extra capacity

Try to future proof your investment by planning how your organisation will change over the next three to five years. If you expect your organisation to grow, you need to ensure you have extra capacity to accommodate this. A good rule of thumb is to oversize a generator by 1.25 times the output of the UPS.

Need some help?

If you want to talk about your standby power requirements, why not contact us? Our experts can advise on the size of generator that will match your UPS.