Differences between Online UPS and Offline UPS

Having a UPS system connected to your office and home equipment is very important, UPS safeguards your equipment against power surges and also keeps the user working as it gives you ample time to save what you are working on.

What is a UPS ( Uninterruptible Power Supply )?

UPS provides a constant supply of power without any interruption. In Normal operation, it draws current from the AC mains, and during a power outage; it draws current from its backup source.

UPS system utilizes DC power stored in the battery as its backup source. The UPS charges the battery from the AC mains through a Rectifier and charge controller circuit. At the same time, it supplies power to the output AC load.

 In case of power failure, the UPS utilizes this charged DC power in the battery and converts it into AC using an inverter, and supplies it to the AC load.

There are several brands of UPS that Mtech Networks deal with, Mecer UPS, APC UPS, Mercury UPS, Tripplite UPS, Eaton UPS and Office point UPS.

Online UPS – ( Mecer UPS, APC UPS, Mercury UPS & Eaton UPS)

Online UPS supplies power to the AC load through the Rectifier and Inverter Combo in normal operation and uses an inverter to supply AC power during a power failure.

 Online UPS output power supply always stays ON and there is no need for switching. Hence, there is no time delay in switching between its sources. There is no interruption in the case of power failure even for a nanosecond.

In case of power failure, the UPS will stop drawing current from the AC mains and stops charging the battery. But the AC load will continuously draw current from the battery through the Inverter.

Online UPS advantages

  1. Online UPS can regulate the voltage correctly
  2. The mains and load are presented separately
  3. There are no fluctuations (dips and surges) in the voltage, which means that the quality of the voltage is stable
  4. The reason for this is that the inverter is always switched into the “on” position
  5. The conversion time from DC to AC is negligible (the same reason being that the inverter is never switched off)
  6. When the utility power goes down there will be a continuation of power and no imbalances will be noted

Offline UPS – ( Mecer UPS, APC UPS, Mercury UPS & Eaton UPS)

Offline UPS is a type of UPS that directly supplies the power to the AC load from the AC mains in normal operation and uses an inverter to power the AC load from the DC battery. Since there are two separate lines of supplies, the output supply must be switched between the two sources.

Offline UPS switching speed of an Offline UPS is around 5ms which is enough to keep a computer from shutting down. But not fast enough to keep a smooth operation of sensitive equipment in hospitals.

Advantages of Offline UPS

  1. Your Offline UPS System is user-friendly and straightforward to operate
  2. Offline UPS is less expensive than the Online UPS option
  3. The efficiency of this system is high. This is because the charger is not constantly on.
  4. These are affordably priced.
  5. The internal controller is simpler.
  6. The power handling capacity of the charger is greatly decreased.
  7. Applications using offline UPS include emergency power supplies, printers, computers, EPABX, scanners, etc.

Differences between Online UPS and Offline UPS

The UPS that supplies power from the AC mains to the load through the rectifier and inverter combinationThe UPS supply the AC mains power directly to the load.
It continuously draws current from the battery.It only draws current from the battery during primary source failure or power outage.
It requires a large battery charger circuit because it carries the entire load current.It requires a small charger circuit because it only charges the battery.
The input supply and the load is completely isolated.There is no isolation between the input supply and load.
It has high-performance output because it protects the output load from input voltage spike and distortion.Its performance reduces with the input voltage distortion; which is directly connected to the load.
There is not switching between the source, hence no time delayIt uses a static transfer switch to switch between its source with a time delay of 5ms
It stays ON almost at all times.It turns ON only at power failure.
Due to its continuous ON condition, it is inefficient and unreliable.It is more efficient and reliable because it mostly stays off.
It requires large heat sinks because of the high operating temperatureIt requires smaller heat sinks because of low operating temperature due to its off state mostly.
The components used must have the tolerance to withstand high temperatureThere is no need for the components to have high-temperature tolerance.
It is expensive than Offline UPS.It is cheaper than Online UPS.
It is used for very sensitive electronics that cannot tolerate any gap between supplies such as in-hospital ICUsOffline UPS is used for electronic equipment that can tolerate a delay of 5ms such as Computer etc