An online UPS is sometimes also known as a ‘power firewall’, as it forms part of the incoming mains power supply connection that powers your equipment, and sits between those sensitive electronic devices and the potentially unreliable mains supply.
If the mains power fails, the online UPS batteries take over seamlessly – the rectifier, which normally charges the DC batteries from the AC supply, simply disconnects from the circuit.
The inverter, which provides an AC output from the DC batteries, carries on supplying the required current so that your equipment continues to operate during the mains power outage.
You might find it helpful to think of an online UPS like a modern ‘always-on’ internet connection – always ready and waiting for you when you need it.
Why do I need an online UPS?
An online UPS means there is no momentary delay during a mains power outage, so the supply of energy to your equipment is continual and should not spike or trough at all, even for an instant.
For the most sensitive equipment, electronics, and life-or-death systems such as in healthcare facilities, an online UPS is one of the best ways to make sure the system stays switched on and operating as normal.
Because of their online UPS design, these so-called ‘power firewalls’ can also tackle other power quality issues, and certain systems should therefore also help to tackle unwanted variations in current or voltage coming into your premises.
Recovering from a power outage
Again, an online UPS is naturally a good option to recover from a power outage and restore the UPS batteries to a full charge ready for the next incident – ideal if you face ongoing power quality issues you need to smooth out.
When the mains power is restored to normal function, the rectifier comes back into effect too, allowing a small portion of the mains electricity to go into recharging any capacity that was used from the UPS batteries during the outage.
Once this is done, the online UPS system as a whole is back to its previous state and ready to provide maximum capacity in any subsequent power outage, all with little to no manual intervention in most incidents.
You benefit from minimal maintenance, immediate protection against power spikes, brownouts and total loss of mains supply, and rapid restoration to full capacity once the mains supply is back and available to recharge the UPS cells.