Page 111 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

Main power supply failure (outage) cannot change the operation mode,

The transfer time is negligible due to the always-on condition,
Wide range of input voltage
Disadvantages of On-line UPS:
Due to Continuous on-mode, it generates more heat. Hence, a large heat sink is required.
It has a Complex design.

It is much more expensive than offline UPS.
3 Line interactive UPS:
In this type, the inverter always charges the battery in the normal voltage range. Nevertheless, as soon as the
input voltage goes beyond or below the normal range, UPS is activated, and supplies the consumer load from
the batteries and prevents damage to connected devices. The interactive line type is mostly used in network
equipment.
Line Interactive UPS Block Diagram:
Line interactive technology UPSs are being used in places where we have sensitive and expensive devices and
equipment because electrical fluctuations will lead Sensitive electrical devices to fail. Thus, they should not be
subject to fluctuations or noises. Line interactive UPSs are usually used for network equipment. For instance, line
interactive UPS is utilized for departmental servers, websites, and small company servers. The line interactive
design is a combination of offline & online schematic. In line with interactive design, the inverter plays a dual role.
First, it charges the battery when the main power supply is flowing. Second, it regulates the output voltage and
works as a normal inverter in the absence of the main power supply.
Line-interactive UPS can remove slight fluctuations in power flow, such as a decrease or increase in voltage
level, without switching to the battery. Line Interactive UPS provides more power protection and reliability than
basic Offline designs. The difference is the addition of a tap-changing transformer, voltage regulator, or Automatic
voltage stabilizer. This tap-changing transformer regulates the voltage by changing the tap depending on the
input voltage. Additional filtering is provided in this UPS, resulting in a lower transient loss. The block diagram is
shown below interesting thing about Line Interactive UPS is that using too much battery can greatly impact on its
lifetime. Moreover, Line-Interactive inverters are usually designed to resupply load current by main supply power
in case of failure in UPS.

Advantages of Line-interactive UPS
1 High reliability and high efficiency,
2 Lower costs than On-line UPS,
3 High power supply,
4 Noise and fluctuation filtering

5 Better protection than Offline UPS
Disadvantages of Line-interactive UPS
1 Line interactive UPS cannot fully filter noise and fluctuation with low power demands (like 5KA and below),

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CITS : E & H - Electronics Mechanic - Lesson 56 - 63