The two primary types of UPS topology used in server/network UPS systems are on-line network and line-interactive. At the basic level, the latter are about 20-40% less expensive than on-line systems, depending on the make and model. Here we look at four key features and how these two different technologies deliver the features to the equipment they are connected to.
Difference Between On-Line Network and Line-interactive UPS
#1 Transfer Time from Line Power to Battery
During outages, a line-interactive UPS system transfers from the line power to battery-derived power in a matter of 2-4 milliseconds. This is typically enough to keep almost all the most power-sensitive equipment functioning without interruption. An on-line UPS system doesn’t have a transfer time because the connected inverter is already supplying the equipment the proper load whenever an outage takes place.
#2 Pure Sine Wave Output
When a line-interactive UPS operates from battery power, it generates the waveform of the Alternating Current output while an on-line Uninterruptible Power Supply System does this continuously. Most line-interactive UPS and all online systems have a pure sine wave output. This output provides the best compatibility with and superior stability for sensitive equipment. Some equipment power supplies also need pure sine wave power and it prevents other systems from malfunctioning, overheating, or failing prematurely.
#3 Surge/Noise Protection
All Server or Network Uninterruptible Power Supply UPS systems include line noise filtering and surge suppression components that protect the equipment from damage that’s caused by electromagnetic (EMI/RFI) line noise, lightning, and surges. An on-line UPS system offers far better protection because it has a double-conversion operation that isolates the equipment from any problems that occur on the Alternating Current line.
#4 Regulation of Voltage
A line-interactive UPS system uses AVR (automatic voltage regulation) to correct any abnormal voltage without actually transitioning to battery power. When voltage is regulated by switching to battery, it ends up draining the backup power and can also result in premature wear in the batteries.
The UPS system detects whenever the voltage crosses a preset high/low threshold value and utilises transformers to either lower or boost the voltage by a specific amount in order to return it to within the acceptable range. An on-line UPS system uses a far more precise voltage regulation method.
It continuously converts the incoming Alternating Current power to Direct Current power. After this the DC power is converted into ideal AC output power. The continuous double-conversion operation efficiently isolates the connected equipment from any problems that exist on the AC line, such as:
- Line noise
- Frequency variations
- Harmonic distortion
- Electrical impulses
- Line noise
When it isn’t operating from the battery power (line mode), a line-interactive Uninterruptible Power Supply system typically regulates the output within a range of ±8-15% of its nominal voltage (such as 120/208/230/240 volts). In comparison, an on-line Uninterruptible Power Supply System typically regulates voltage within a range of ±2-3%.
Choosing the Right UPS for your Needs
Both on-line and line-interactive systems have specific uses and the type of setting, the equipment used and your preferences and budget will decide what type of system you opt for. It’s important that you discuss your requirements with our team. They will understand your needs and provide information on the different types of system and their recommendations on which system will work best for you.
If you want to know anything more about any of our products and services, don’t hesitate to contact us at KaRaTec Power Supply Pty. You can give us a call at 612 9808 1127. You can also fill in this contact us form and we will respond within the shortest possible time to help you with the guidance and information you need.
Thanks for reading,
Karatec Power Supply Pty
612 9808 1127