5 Types of Common Uninterruptible Power Supplies in Singapore

5 Types of Common Uninterruptible Power Supplies in Singapore

5 Types of Common Uninterruptible Power Supplies in Singapore

Introducing the UPS

A UPS is a device that provides emergency power to a load (such as a computer, server, or other critical electrical equipment) when the input power source or mains power fails. In other words, it is a backup battery system that keeps the connected equipment running for a limited yet substantial amount of time during a power outage.

A UPS has many components, but in its most basic form it would generally consist of a battery, a rectifier, an inverter, and a control unit. When the mains power is stable, the rectifier converts the Alternating Current (AC) input to Direct Current (DC), which is then stored in the battery. When a power failure happens, the inverter in the UPS takes over and converts the stored DC power back to AC to supply the connected equipment with the power that it needs. The control unit manages the charging of the battery and the switchover between the mains power and the battery power.

UPS devices can provide a plethora of benefits to users, including protection against any unpredictable power outages and voltage fluctuations, protection against data losses and corruption, as well as vastly improved equipment reliability and uptime. They can also be used as a means of providing power conditioning and surge protection, while helping to ensure the safety and longevity of connected equipment. UPS devices are commonly used in data centres, telecommunications facilities, and other environments where equipment failure or data loss can have deleterious ramifications and should be avoided at all costs.

UPS devices can function perfectly well as stand-alone units, but in many cases they are instead integrated into larger power protection and backup systems, especially in situations of a larger and more complex scale. Here is a list of the 5 most common types of UPS in Singapore, as well as their various defining characteristics.

  • Line-interactive UPS
  • Standby UPS
  • Standby-ferro UPS
  • Double-conversion online UPS
  • Delta conversion online UPS

1. Line – Interactive UPS

A line interactive UPS is an extremely common device used to provide uninterruptible power supply in Singapore, and provides power protection against power outages and voltage fluctuations. It works by continuously monitoring the incoming AC voltage and, if necessary, regulates it to a stable level. Unlike an offline UPS, a line interactive UPS is capable of providing some level of voltage regulation without switching to battery power. This makes it a good choice for applications that require power protection with a lower budget or for those that need to keep their devices running for a short time during a power outage


2. Standby UPS

A standby UPS is a type of power backup system that provides basic power protection against short outages and brownouts. It works by switching to battery power when the incoming AC voltage drops below a certain level or fails completely. Standby UPS systems are typically less expensive than line interactive or double-conversion online UPS systems and are suitable for applications that require minimal power protection, such as home computers or small electronics. When the incoming AC power is stable, the battery is not in use and the equipment runs directly on AC power. Standby UPS systems are also known as “offline UPS” or “basic UPS”.

3. Standby-Ferro UPS

A standby ferro UPS functions similarly to the aforementioned standby UPS, but the term “ferro” refers to the use of a ferroresonant transformer in the UPS design, which provides voltage regulation and filtering. Standby ferro UPS systems are typically less expensive than other UPS devices like line interactive UPS systems, and are suitable for applications that do not require a lot of power protection or non-critical applications where 100% uptime is not needed. However, it is worth noting that this particular UPS is not very widely-used due to it being generally less efficient than the other options in this list.

4. Double – Conversion Online UPS

A double-conversion online UPS is a type of power backup system that provides the highest level of power protection and reliability. It works by continuously converting incoming AC power to DC power and then back to AC power. This double-conversion process ensures that the connected equipment receives clean, stable power at all times, even in the event of a power outage or voltage fluctuation. The online design means that the UPS is always providing power to the connected equipment, and the battery is used only as a backup in the event of a power failure. This type of UPS is commonly used in mission-critical applications, such as data centres, medical equipment, and financial systems, where any kind of downtime is avoided as much as possible. Here in Singapore uninterruptible power supply devices like these are widely used.


Delta-Conversion Online UPS

The delta-conversion online UPS is a recently-developed UPS device designed to build upon the key defining features of the double-conversion online UPS, while making further improvements and refinements. While the load voltage of the delta conversion online UPS is always being supplied by the inverter, the addition of a second component – the delta converter – means that additional power is being contributed by the delta converter to the inverter output. In the event of an AC failure, this design will behave similarly to the double-conversion online UPS.


In conclusion, each of the 5 UPS devices mentioned above have their own key features, and each of them have their own use cases. For instance, if the equipment in question is of critical usage and requires constant uptime without any issues, it is thus advisable to consider utilising either double-conversion online UPS devices or the newer delta-conversion online UPS devices, due to their ability to provide stable power at all times with minimal fluctuation. On the other hand, if cost is a significant constraint and the equipment in question does not require high levels of protection, then it would be better to consider more cost-effective UPS devices such as the standby UPS devices.

Overall, choosing suitable uninterruptible power supplies and devices will ultimately depend on your use case and the individual requirements of the equipment being used.