Generators can produce what’s often referred to as “dirty” power. This term is used to describe power that is inconsistent with standard voltage and frequency levels. Generators, particularly during their start-up phase, can produce power with voltage and frequency fluctuations outside the range accepted by many electronic devices. This can be due to several factors, such as load changes, fuel type, and quality of the generator itself. These fluctuations, if severe, can lead to operational issues or even damage sensitive electronic devices, including the UPS that is plugged into them.
Standby, or offline, UPS systems will have trouble recognizing the “dirty” power from a generator as a valid power source. This can cause the UPS to remain on battery power even when the generator is running, leading to a premature draining of the UPS battery. Standby UPSs are designed to switch to battery power when they detect an interruption or significant deviation in input power, and the irregularities in generator power can trigger this switch. The UPS may also repeatedly switch back and forth between line and battery power, it will struggle to decide whether the generator power is acceptable, leading to wear and tear on the UPS and its connected equipment. For these reasons, when using a generator as a backup power source, use a more robust type of UPS, such as a line-interactive or double-conversion UPS, which are better equipped to handle the irregularities of generator power. Remember to set the power quality to low (if the UPS has the setting), that will help avoid unnecessary switches from utility power to battery power by the UPS.
