We provide uninterruptible power supplies (UPS) from global brands, including Eaton, BB, Schneider, and Emerson, ranging in size from 1 kVA to 1000 kVA.

What are uninterruptible power supplies?

Uninterruptible power supplies (UPS) are clean, stable, and readily available electrical power sources in the event of a power outage. They can generate 110 volts AC, the voltage needed to operate equipment for a limited period until power is restored. An uninterruptible power supply typically includes a battery to provide primary backup power. The remaining power from the battery is converted to AC by an electronic voltage converter. In addition to providing backup power, an uninterruptible power supply typically protects your equipment and peripherals from damage caused by poor power quality, lightning strikes, and other factors.

Not all UPS systems are the same, and protecting your equipment requires finding the right solution. Some parts of the process are simple, such as determining the battery life you need, while others are more complex, such as determining whether you need offline backup, online backup, or line-interactive. We'll explain the types of UPSs and what you need to know about choosing one.

Types of Uninterruptible Power Systems

Offline or standby systems

These are the simplest and least expensive option. They typically remain in sleep mode while the system uses wall power. When wall power is interrupted, an automatic transfer switch begins drawing power from the UPS unit. When AC power from the wall returns, the transfer switch reverts to wall power, and the UPS returns to sleep mode.

These systems provide battery backup and surge protection with high efficiency. While an offline UPS system starts up in seconds, it doesn't provide the instantaneous transfer required by many electronic devices. It may offer limited protection, but it's a good option for low-power devices such as computers or office equipment.

Online or Double Conversion Systems

The most common type of UPS is an online system, also called a double conversion system. An online UPS system keeps a DC-AC inverter running at all times to provide clean AC power to the user. Because the inverter is always on, there's no transfer time required. During a power outage, the user can continue working and may hear beeps alerting them that they are running on backup battery power. Otherwise, their computer or printer won't notice any difference.

These systems are typically the most reliable, offering protection against all major outages, making them the ideal choice for UPS systems.

Again, not all online or double-conversion UPS systems are the same. Some are very small, while others are bulky. The difference lies in the presence of modified sine waves and true sine waves, the latter being larger and more expensive. Some devices, such as hand tools and laptops, may not respect the above distinction. For high-performance systems, it is advisable not to compromise on backup power quality, so pure sine waves are preferred.

Line-Interactive Systems

Line-interactive UPS systems can handle minor glitches and distortions in wall AC power by immediately collecting a portion of the lost or distorted AC cycle and adding it to the main power supply. These systems use an electronic transformer and a multi-port variable voltage autotransformer. Because this system runs on AC wall power, it doesn't require a battery. Therefore, it can only partially perform the function of a UPS, and therefore cannot be considered a true UPS. It's more appropriate to call it a power conditioner.

A line-interactive UPS is a good option for medium-duty protection against surges and providing backup batteries in the event of a complete outage. These units also eliminate switching times. However, they are heavier and larger than both online and offline UPS systems.

How to Choose the Right UPS System

Standards and Regulations

Many industries have specific standards that your UPS must meet to ensure power delivery in critical applications, such as medical equipment and military operations. Regulations or standards may require the use of a power supply with specific technologies, such as instantaneous switching or pure sine waves, to ensure the continued operation of critical equipment.

UPS System Type

Determine the most pressing issues in your situation. If your incoming power surges and drops frequently and in small amounts, consider a line-interactive UPS system. If it causes harmonic distortions, line noise, or frequency variations, you may need a double-conversion UPS system. An offline system may be ideal for minor power outages and voltage drops.

Battery Life

Are you more concerned about having enough time to turn off some critical electronics to save data, or do you need to wait for an emergency generator to come on? Determine the time you need and choose a short- or long-term backup power supply with a large battery. Higher-wattage loads drain your battery faster.

Sine Wave Requirements

An uninterruptible power supply (UPS) generates either simulated sine waves or pure sine waves. Simulated sine waves may have gaps between cycles that can cause problems for your system, while pure sine waves are considered more reliable for sensitive electronics, such as devices with AC motors and some types of medical equipment. Without pure sine waves, you may experience shutdowns or stress on your devices.

The quality of the available AC power can sometimes become critical. What may appear to be a normal 110-volt AC source may not actually be a pure sine wave source, and some systems may experience problems with it. These systems may malfunction, display errors, or simply fail to perform properly. Medical diagnostics, devices, and delicate moving parts driven by precision motors, and the like can be sensitive to the quality of the AC waveform. A pure sine wave is considered ideal, and some manufactured sine waves may not be ideal but may ultimately perform well. The system engineer determines what is appropriate for his or her system.

Replacement Costs

Calculate the value of everything that relies on wall power for operation. Create a feasibility study of how your UPS system mitigates risks and what critical resources it might protect, including the equipment itself, data loss, and downtime costs. Consider how each type of power outage, such as harmonic distortion or slow switching times, will affect the electronic devices you use.