How does a UPS Systems Work?

A running power source, also running power supply, flywheel/battery backup or UPS, is an electrical device that offers emergency power when the utility mains, or input power source malfunctions when you least expect it.

A UPS is different from a standby generator or emergency or auxiliary power system in that it offers near-instantaneous or instantaneous protection from input power intermissions by using one or more connected batteries and other supplementary electronic circuitry for low power consumers, and or by using flywheels and generators for high power consumers.

The battery runtime of many running power sources is around 5-15 minutes which is characteristic when it comes to smaller units – but enough to allow time to bring a supplementary power source up and running before anybody notices, or can be used to shut down the protected equipment correctly.

Although a UPS system isn’t limited to defending any specific type of equipment, it’s usually used to protect telecommunication equipment, data centres, computers or other electrical apparatus where an unforeseen power interference could cause fatalities, injuries, business interference and/or data loss. UPS systems range in size from those made to safeguard a computer without a video monitor (about 200 VA rating) to big units used to power buildings (>300kVA), entire data centres (>1MVA), or manufacturing processes.

Different Types of Ups Design

The three common categories of contemporary UPS systems are line interactive, on-line or offline/standby.
An offline/standby UPS unit is powered by the input power directly and the backup power circuitry is only initiated when the power stops working. Many UPS systems under 1 kVA are on the standby variety or line-interactive which are often cost-effective.

A line interactive UPS system keeps the inverter aligned and redirects the DC current of the battery from the standard charging mode to distributing current when the power fails.

An on-line UPS utilises a ‘double conversion’ technique of receiving AC input, correcting to DC for passing through battery strings (or rechargeable battery), then reverse it to 120V/240V AC to power the protected device.

For bigger power units, dynamic continuous power supplies are used sometimes. An alternator/synchronous motor is attached to the mains through a choke. Power will be stored in a flywheel. When the mains power stops working, an Eddy-current control keeps the power on the load. DUPS can be integrated or combined with a diesel-generator, which forms a diesel rotary continuous power supply, or DRUPS.

Recently, a fuel cell powered UPS has been developed using a fuel cell and hydrogen as a power source, offering long run times.

Standby/Offline UPS design

The Standby/Offline UPS design (SPS) has standard features, which are battery backup and surge protection. Also taking in to consideration you may need a ups battery replacement. This UPS type functions when a user’s equipment is connected to an incoming utility power source with the same transitory voltage clamping equipment utilised in a standard surge protected plug strip attached across the power line.

When the receiving utility voltage gets below a set level the interior SPS switches on its DC-AC inverter that’s powered from an interior storage battery. The SPS automatically turns the connected equipment on and to its DC-AC output inverter. Depending on the duration of time it will take the Standby UPS to discover the lost utility voltage, the switchover can reach up to 25 milliseconds.

In general, depending on UPS’ connected load size and the sensitivity that the attached equipment will have to voltage variation, the UPS will be made and/or provided (specs wise) to include particular ranges of equipment like Personal Computer, without any brownout or dip to that equipment.