UPS is a device that provides battery backup when the electrical power fails or drops to an unacceptable voltage level.

Small UPS systems provide power for a few minutes; enough to power down the computer in an orderly manner, while larger systems have enough battery for several hours. In mission critical datacenters,
UPS systems are used for just a few minutes until electrical generators take over.
UPS systems can be set up to alert file servers to shut down in an orderly manner when an outage has occurred, and the batteries are running out. Surge Suppression and Voltage Regulation A surge protector filters out surges and spikes, and a voltage regulator maintains uniform voltage during a brownout, but a UPS keeps a computer running when there is no electrical power.
UPS systems typically provide surge suppression and may provide voltage regulation.

There are four types of UPS (uninterruptible power supplies). DELTA UPS products are based on the most reliable, flexible and robust of these four technologies – true on-line UPS.

DELTA UPS provide double-conversion on-line power protection to keep computers and communications systems running seamlessly without interruption – in the harshest conditions.

Additionally, DELTA uninterruptible power supplies can automatically register, condition and convert irregular or international power input.

DELTA UPS units add the ability to take in both DC and AC and give back DC and AC. This is important for clients with complex computer and communications systems.

DELTA uninterruptible power supplies can accept power from a wide variety of sources worldwide—AC from 40 to 400 cycles per second and 80-265 volts, plus DC from 22 to 32 volts. The UPS then can give back pure 50 or 60 cycles AC at 110 or 230 volts, and DC at 12, 24, 28, or 48 volts. Customers appreciate that level of flexibility and the fact they do not have to carry added power converters.

The four UPS types are:

Standby UPS— The Standby or off-line uninterruptible power supply (UPS) is the simplest and least expensive type of UPS. The back-up battery is not connected to the circuit until a power interruption occurs. At the point when power is disrupted, a transfer switch closes and the battery supplies power. However, there is an unavoidable momentary loss of power as the switch closes. That momentary loss generally is unacceptable to modern computing and telecommunications equipment. A Standby UPS also does not sufficiently protect against voltage sags and low frequency conditions that can occur short of an actual loss of power, all of which can damage sensitive digital equipment.

Ferroresonant UPS— A slight improvement over Standby UPS, the Ferroresonant uninterruptible power supply (UPS) uses a three-coil transformer which acts like a fast switch upon loss of power. However, this UPS does not sufficiently protect against voltage and frequency variations.

Line-Interactive UPS— Line-interactive uninterruptible power supplies (UPS) use a continuously running on-line battery with an inverter/converter to keep the battery connected to the output. It provides instantaneous back-up, but is only marginally effective for voltage and frequency problems. By frequently going to battery and draining that power source, these UPS run the risk of not operating during a power outage.

DELTA True On-line UPS— DELTA true on-line uninterruptible power supply (UPS) provides the highest level of power protection of the four UPS types. Through a process of double conversion, all AC input is converted to DC and then back to AC at the proper voltage and frequency – providing both conditioned electrical power and protection against power outages. Since the battery is always in the circuit, there is instant back-up without any loss of power. This design is like the system in a laptop computer. The laptop gets its power from the battery. The battery can be continuously recharged from the AC charger. The laptop keeps running uninterrupted even if the power cord is unplugged.

All three major topologies perform a basic level of power protection for computers and other sensitive electronics. Users who do not require the highest possible power availability to the critical load have options such as off-line or line-interactive UPS devices.
The off-line UPS is so named because the battery and/or the inverter are not supplying power to the load except when the utility “fails.” The failure of the utility requires the switch to transfer to inverter. The inverter then starts and runs the load. The total transfer time after the command to switch is usually well less than a half cycle or eight milliseconds @ 60Hz and 10 milliseconds @50 Hz. The required decision and transfer time are usually acceptable for most electrical loads. Off-line, (also called stand-by), is a cost-effective choice for small, non-critical stand-alone applications, for example, isolated PCs and peripherals.
A well-designed line-interactive UPS utilizes the bi-directional inverter to perform two functions, namely to run the load and to charge the battery. As the name implies, the inverter “interacts” with the utility to maintain nominal output voltage to the load. An ability to interact with the utility supply improves the overall UPS performance over that of the off-line products. Line-interactive UPS devices offer protection against wide input voltage swings, sustained brownout and single-phase conditions. For many users, the line-interactive UPS represents a very good level of protection for a moderate investment. However, buyers should be aware that present line-interactive technology does not perform at the level of an on-line UPS.
True on-line UPS features an inverter that is on-line all the time, as well as a battery that is always in the energy power circuit and not separated from the inverter by switching means. The smooth, solid and repeatable performance of this topology yields a number of tangible benefits, particularly worthwhile for mission-critical applications. These include:
Superior battery life.
Superior line/load isolation, resulting in more stable output voltage.
Superior reliability with simpler controls and no switching required for battery operation.
Wide input voltage range which optimizes battery life and potentially reduces battery costs by up to 75%.
Assured reliable performance of the critical load by properly maintaining the required output voltage and providing more stable controls.
All major topologies — off-line, line-interactive, on-line and hybrids — work. The question is whether a given topology is appropriate for a given application. A true on-line UPS is most appropriate for truly mission-critical loads, or applications which require high availability. If on-line UPS performance is a requirement for the levels of availability expected of the computer/technology investment, then the UPS must be “on-line” in the traditional sense. When high reliability of electric service is required, switching between alternate energy sources is not acceptable
What is Harmonics (current and voltage)? All alternating current which is not absolutely sinusoidal is made up of a fundamental and a certain number of current harmonics which are the cause of its deformation (distortion) when compared to the theoretical sine-wave
Thanks to DSP controlled power factor corrected IGBT rectifier provides us higher input power factor, lower input current total harmonic distortion, wide input voltage and frequency tolerance. Inform UPS systems provide ≥0.99 input power factor PFi, and ≤ 5% input current total harmonic distortion THDi. High power factor helps you to consume less reactive power and pay lower electrical pay out. It provides minimizations of cable cross-sections, associated switchgear, transformer and generator sizing requirements. Low input current THDi avoids disturbance to other loads connected upstream the power distribution bus and interference reflected to the mains.

The primary purpose of generator system as well as the UPS system is the same – to provide backup power. During power outages, the electronic devices are protected from damages and are able to work with such kind of alternate power resources. Yet, there are few major differences between the generator system and the UPS system that causes the dissimilarity in few of their applications.

Comparative Features of the Generator System:
It can be either portable or of the standby type; depending upon the size.
The working principle involves conversion of mechanical energy into electrical energy.
The reliability of the backup power mainly depends on sizing of the generator system.
There is a choice of either a manual switch or an automatic switch to turn on the generator system in case of power failure.
There may be emission of harmful gases during the course of its working.
Most of the generators produce unpleasant noise while in operation. The generator system provides backup power for a very long time. It also serves as an alternate power source.
Comparative Features of the UPS System :
The UPS system is most often portable, due to its smaller size.
The working principle involves conversion of the alternating current (AC) into direct current (DC); which is then stored as chemical energy in the batteries. This energy is further converted to DC which in turn is supplied to the device.
The reliability of the UPS system mainly lies on the proper functioning and operation of its battery.
Automatic switches are inbuilt into the UPS system to provide the immediate power backup in case any disruption or failure in the primary supply.
It is free from any kind of emission during its functioning.
The UPS system does not cause any disturbing noise while in operation.
The backup power offered by the UPS system is for a shorter duration. Most often it is enough to ensure the safe shutdown of the connected devices.
With the basic knowledge about the primary differences between the generator and the UPS system, it will be easier to make the choice that best fulfills your backup power needs.

1- If you have a limited budget, choose a standby (also called “off-line”) UPS that switches to battery power when power goes out.

2- Choose an “on-line” UPS if you need unlimited backup power.
3- Select a “line-interactive” UPS if your needs fall between the two other types.
4- Determine the total power needs (in watts and volt-amperes) of equipment you will connect to the UPS.
5- Choose a UPS that equals or exceeds the total power requirements of the equipment that you’ll connect to it.
6- Compare the following five specifications for different models: maximum surge current (expressed in amps – more is better), surge suppression (expressed in joules – more is better), suppression response time (faster is better), battery recharge time (faster is better), and number of AC outlets (more is better).
7- Find out if the unit under consideration has a replaceable battery, and if the battery is user-replaceable.
8- Compare battery operating times (how long the UPS will keep equipment running after power failure).
9- Look for a unit with modem surge protection and electromagnetic interference (EMI) and radio-frequency interference (RFI) noise reduction if you need those features.
10- Check for alarms or LEDs that indicate wiring problems, whether the equipment is running on UPS battery, and whether the battery is low.
11- If you are buying a more expensive unit, get one with software that automatically saves documents, closes applications, and turns off equipment when power goes out.
12- Compare warranties and insurance guarantees.

While highly useful, electricity can be very dangerous, causing fires, shorting out equipment and injuring users. Power systems also are not always very reliable. Static voltage regulators are designed to help create reliable and predictable power while also reducing the risk that the electrical system will cause injuries.

Electricity Regulation 
 
Power systems are “regulated” when the static voltage regulators very quickly respond to fluctuations in power to create a constant voltage, according to DELTA INC.. This control is carried out with the use of a gas-filled regulator tube, according to the Virtual Institute of Applied Science.
Coil Transfer 
 
The static voltage regulators are designed to have wide input voltage range and reliable output voltage stability using a system of changing coils, according to DELTA INC. The equipment attached to the regulator has its electricity transferred to an auto-transformer, which changes the coils and prevents sudden fluctuations in the voltage, thus making the electrical systems safer.
Efficiency
The static voltage regulators are designed to not place a lot of burden on the electrical systems that they are a part of, according to DELTA INC. They operate very quickly because they have a thyristor that increases the speed of responses in the voltage charges. The inductor and the capacitor on the voltage regulator do not send very much electricity back and forth between each other, so these regulators place very little burden on the regulator, according to the Virtual Institute of Applied Science.
Control 
Static voltage regulators are controlled by microprocessors, which are very small computer processing systems. These microprocessors not only allow the regulators to be controlled but also record the operations of the static voltage regulator, according to DELTA INC. Static voltage regulators usually function automatically, though they also usually have features designed to allow the owner of the regulator to take manual control. Remote monitoring is possible through serial and dry contact ports. These regulators are also supposed to have a manual bypass switch.
High Temperatures
Static voltage regulators are designed to operate at very high temperatures, according to DELTA INC. Electrical systems are used a variety of environments and industrial situations that use a lot of electricity to produce a lot of heat, which increases the chances of electrical fluctuations.
Safety
Even though the static voltage regulator is designed to make electrical systems safer, safety precautions should be followed when using the voltage regulator. The voltage regulator should not be operated when it is wet, according to Inform UPS. This machine should also always be connected to the ground so that it can disperse electrical charges into the ground.