uninterruptible power supply

Uninterruptible power supply (UPS) is a device that, thanks to its batteries or other energy storage elements, can supply electrical power for a limited time and during a power failure to all devices that have connected. Other functions that can be added to these equipments is to improve the quality of the electrical energy that reaches the loads, filtering rises and downs of voltage and eliminating harmonics of the network in case of using alternating current.UPSs provide electrical power to equipment called critical loads, such as medical, industrial or computer equipment, which, as mentioned above, always require power and quality, due to the need to be at all times operational and without failures (spikes or voltage drops).The unit of power to configure a UPS is the volt-ampere (VA), which is the apparent power, or watt (W), which is the active power, also called effective or efficient power, consumed by the system. To calculate how much power a UPS equipment requires, you must know the consumption of the device. If the known is the effective or effective power, in watts, multiply the number of watts by 1.4 to take into account the maximum power peak that can reach the equipment. For example: (200 v × 1.4 A) = 280 VA. If you find the nominal voltage and current, to calculate the apparent power (VA) you have to multiply the current (amperes) by the voltage (volts), for example: (3 amps × 220 volts) = 660 VA.Types of UPSUPS of direct current [edit]The loads connected to the UPS require a direct current supply, so these will transform the alternating current of the commercial grid to direct current and use it to power the load and store it in its batteries. Therefore they do not require converters between batteries and charges.Mainly there are 3 types of UPS, and each of them corrects different common faults in the electricity supply.UPS types:    SAI offline. The UPS of this typology corrects the following electrical faults        Feed Failures        Voltage drops.        Peaks, surges and undervoltages.    SAI Line Interactive. The UPS Line interactive corrects:        Feed Failures        Voltage drops.        Peaks, surges and undervoltages.        Prolonged outbreaks.        Prolonged overvoltages.    UPS online. This type of UPS is the safest and the most electric fault corrects.        Feed Failures        Voltage drops.        Peaks, surges and undervoltages.        Prolonged outbreaks.        Prolonged overvoltages.        Distortions in the wave of the line.        Variations in frequencies.        Microcuts.        Harmonic distortion.    Common faults in the electric power supply    The role of the UPS is to supply electrical power at times of failure of supply, in a "short" time interval (if it is a failure in the supply of the network, until isolated emergency systems start operating). However, many UPSs are capable of correcting other supply failures:        Power cut - total loss of input voltage.        Overvoltage: occurs when the voltage exceeds 110% of the nominal value.        Voltage drop: when the voltage is less than 85-80% of the nominal.        Voltage spikes.        Electrical or electromagnetic noise.        Frequency instability.        Harmonic distortion, when the supplied sine wave does not have that shape.    Manufacturers of UPSs usually classify equipment based on electrical faults they correct. It is possible to obtain a voltage regulator that in addition to avoiding electrical overloads, keep the equipment running in the event of a power failure for several minutes.