The lowdown on transformer-based versus transformerless UPS

What’s the difference, why does it matter and what happens if you use the wrong one?

By Robert Brand, UPS & Infrastructure Product Specialist at Drive Control Corporation

Given the instability of electricity in South Africa and up into the continent, the UPS has become a vital piece of technological equipment in Africa. Not only is it essential for protecting expensive computer equipment from fluctuations in power, it is also necessary across industries such as manufacturing, factories and warehousing, where equipment needs to be powered by a steady and constant electricity supply. However, given the diversity of the applications to which a UPS can be applied, it makes sense that there are different types of devices applicable in different scenarios. Transformer-based and transformerless UPS’s might perform a similar function on the surface, but they have very different applications, and using the wrong device in the wrong scenario can cause major business issues.

The difference between a transformer-based and a transformerless UPS is exactly what the names suggest. One type of UPS uses a transformer, and the other type does not. The presence of a transformer means that the UPS physically isolates the mains voltage from the load through a series of copper windings. A transformerless UPS will try and perform the same function electronically. This basically translates to the fact that a transformer-based UPS is more robust and rugged, while a transformerless device typically exhibits slightly higher efficiencies, meaning that each is suited to different applications and environments.

Transformer-based UPS devices use copper windings, a proven, stable technology that has not changed in many decades because there is no need to change it for certain environments. These devices are more suitable to dirty power environments, applications such as mining, manufacturing and heavy industry, and areas where power is highly unstable. For example, many factories and warehouses need to charge huge devices like forklifts. Plugging these devices into the mains will cause massive fluctuations in power, which the UPS then needs to be able to stabilise.

Transformerless UPS devices on the other hand have been designed specifically for the IT environment, and are more suited to data centre and server environments. These devices are not as robust, having been designed to sit inside server rooms, but are easier to manage, and incorporate intelligence and reporting capabilities and the ability to alert people via email or SMS should the power go down, amongst other features. This makes the transformerless UPS ideal in computer and server environments.

Despite these differences, however, many organisations apply the wrong type of UPS in a given scenario. While transformer-based UPS devices can handle greater power fluctuations, they are not suited to highly sensitive data fluctuations. Even in areas where power is highly unstable or prone to outages, a transformerless UPS is more applicable, and may require the addition of a voltage stabiliser to ensure it keeps running. If on the other hand users try to apply a transformerless UPS in manufacturing, or in rural areas, these devices will inevitably fail, as they are incapable of handling the voltage fluctuations.

While transformer-based UPS devices use old technology, and transformerless UPS’s are the result of newer technology, miniaturised equipment and modern business needs, the difference does not even come down to pricing. Depending on the manufacturer and the vendor, the price of each different type of device can vary widely. Ultimately, choosing the right type of UPS boils down to knowing your environment and knowing what you need.

Transformer-based UPS’s are the utility vehicle of the UPS industry, and transformerless UPS’s are like a fancy, low slung sports car. You wouldn’t take your sports car offroad into the veld, and you wouldn’t park your dirty, mud-splattered, hard-wearing utility outside a fancy French restaurant on a date. Each type of UPS has its own use, and organisations need to understand these uses so that their expectations of features, functionality and durability are in line with what can be delivered.