What is offline UPS?

What is offline UPS?

The Offline UPS functions by directly providing the AC power to the device connected to the load. During normal operation, the AC power is supplied directly to the load, while the battery is charged with the help of the rectifier circuit.

However, in the event of a power outage, the Offline UPS switches the position of the transfer switch to connect the load to the battery backup path. The charged battery then supplies DC power to the inverter, which converts it into AC and supplies it to the load terminal.

Benefits of Offline UPS

• One significant advantage of the Offline UPS is its low design cost in comparison to the Online UPS.
• The internal control of the Offline UPS is simple, as there are only two paths, which work at different times according to the position of the transfer switch.
• The efficiency of the Offline UPS is high because the battery backup and inverter are not always ON, as they are in the case of the Online UPS.

Drawbacks of Offline UPS

• The electric signal obtained from the Offline UPS has poor quality because the inverter is not always ON.
• In case of power outage, the transfer time is approximately 5ms, during which there will be no output power. There will be a slight disruption in the output power due to transfer time.
• Since the Offline UPS directly supplies AC power when it is available, any spikes or surges present in the input voltage will also be transmitted to the output circuit.

Comparison of On-Line and Off-Line UPS

1. Performance Comparison

• Efficiency: On-Line UPS is generally more efficient than Off-Line UPS due to the continuous regulation of the power supply.

• Power protection: On-Line UPS provides a higher level of power protection than Off-Line UPS, making it suitable for critical equipment.

• Voltage regulation: On-Line UPS can regulate the output voltage, ensuring that the connected equipment receives stable power, while Off-Line UPS cannot regulate voltage.

• Switching time: On-Line UPS has a seamless transition between power sources, while Off-Line UPS has a delay in switching to battery power.

2. Cost Comparison

• Initial cost: On-Line UPS is generally more expensive than Off-Line UPS due to the higher level of power protection provided.

• Operating cost: On-Line UPS consumes more energy than Off-Line UPS, resulting in higher operating costs.

3. Application Comparison

• Suitable applications for On-Line UPS: On-Line UPS is suitable for critical equipment such as servers, medical equipment, and industrial machinery.

• Suitable applications for Off-Line UPS: Off-Line UPS is suitable for basic power backup needs such as desktop computers and small appliances.

Key Difference Between Online UPS and Offline UPS
 

The main differences between Online UPS and Offline UPS are in their operation. Online UPS supplies AC power through a rectifier and inverter circuit even when AC mains power is available, whereas Offline UPS directly supplies AC mains power to the load circuit when the power supply is available. Transfer time is a crucial factor that distinguishes the two types of UPS. Online UPS has zero transfer time as there is no switching between the inverter and mains supply path, while Offline UPS has a transfer time of approximately 5ms.

Another significant difference is that the inverter in Online UPS is always ON, while the inverter in Offline UPS is only active during power outages. Online UPS is generally more expensive than Offline UPS. However, the efficiency of Offline UPS is generally higher compared to Online UPS because the inverter and rectifier circuit are not constantly active in Offline UPS.

Conclusion

In conclusion, both Online UPS and Offline UPS are important for providing uninterrupted power supply. The choice between them depends on the specific application requirements. Offline UPS may be suitable for applications where a slight transfer time delay and cost-effectiveness are acceptable. On the other hand, Online UPS may be necessary for critical applications such as medical equipment, industries, and telecommunication, where even a slight transfer time delay is not desirable, despite the higher cost.

FAQ-

What is the meaning of offline UPS?

An offline UPS, also known as a standby UPS, is designed to provide power to connected equipment only when there is a power outage. When power is present and stable, the UPS is "offline" and does not provide any power to connected equipment.

What is the advantage of offline UPS?

The advantages of offline UPS systems are that they are cheaper to purchase, and without the charger and inverter being permanently on load, they are more economical and energy efficient.

What is an online UPS?

An Online UPS is a type of uninterruptible power supply that utilises either a double or delta conversion technology. With double conversion, network equipment does not receive electricity directly from the AC outlet. Instead, AC power travels to a rectifier, where it becomes DC power.

What is the purpose of offline?

In the offline state, or "offline mode", users can perform offline browsing, where pages can be browsed using local copies of those pages that have previously been downloaded while in the online state.

Can I use offline UPS for PC?

Protect your electronic devices and appliances at home with an offline UPS system. Whether it's for powering your computer, router, or entertainment system, an offline UPS ensures uninterrupted operation during power outages.

Why online UPS is expensive?

Online UPS continuously converts power, while Offline UPS switches to battery mode during a power interruption. Why is Online UPS more expensive? Due to its continuous conversion mechanism and better protection features, Online UPS systems tend to be more costly.