What is a UPS? The three architectures explained
Most buyers ask only two questions — how much, and how many watts. But two machines both labelled 1000 VA can protect your equipment very differently, and the difference comes down to architecture.
In one line
A UPS (uninterruptible power supply) takes over the supply within milliseconds when the mains fails or misbehaves. It delivers two things: your equipment does not lose power during an outage, and the unstable mains is cleaned up the rest of the time.
Three architectures, three very different jobs
| Architecture | How it works | Power quality | Typical use |
|---|---|---|---|
| Offline / standby | Mains feeds the load directly; it switches to battery only on failure | Basic | Home computers, routers, small devices |
| Line-interactive | Mains passes through voltage regulation before feeding the load; switches on failure | Better | Workstations, network cabinets, small servers |
| Online double-conversion | Mains is always converted to DC and back to AC, so there is no transfer | Best | Machine rooms, medical, production lines, critical equipment |
Transfer time is the key difference. An offline unit has a 4–10 ms transfer delay; an online unit has none at all. For an ordinary computer those milliseconds usually go unnoticed — but for medical equipment, precision instruments and some industrial controllers, they can trigger a restart or a false action.
Four common misconceptions
- "A UPS is just there so I can keep using my computer during an outage." True for small equipment, but in a machine room or on a production line the more important value is buying time for a safe shutdown and filtering out voltage faults.
- "Buying a bigger wattage is safer." Oversizing wastes money and keeps the battery in a long-term shallow-discharge state, which actually lowers efficiency.
- "Once a UPS is installed, it looks after itself." Batteries are consumables. Without testing and replacement, your equipment still drops out during an outage three years later.
- "The more expensive the UPS, the better." Choose the architecture to match the load and the power quality it needs, not the price.
If you are not sure which class fits your equipment, send us the load list and an engineer will work it out with you. The individual units are on the full model list, and the range itself is under UPS products — or just ask us directly.