Our tips for Sizing a Generator

generatorOne way to supply power to your electrical equipment beyond the run time of your UPS is to use a generator. This will maintain the power supply to your equipment during lengthy power outages and can eliminate the need for an orderly shutdown. When synchronized with a generator, your UPS will accept the load and support the sensitive electrical equipment or critical systems that can’t withstand a short break in power. The UPS acts as a power bridge, keeping critical systems operational until the generator picks up the load.
Sizing your generator
The most important thing to remember is that your generator size must exceed your UPS power rating. This is because it needs to support both the UPS power rating and an additional 20%-30% to cover the power conditioning process.
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.
If the generator is working close to full capacity, there is a chance that it will drop the load. To avoid this you need to increase the size to allow for synchronisation with the electrical current supplied by the UPS.
When the generator is running, it’s typical for the temperature in the room to rise by 10°C. Add this to the ambient temperature, and it will be running in 30°C heat. To overcome this, you’ll need a larger unit 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 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.