First of all, this model is implemented in non-critical electrical situations, such as small businesses and domestic equipment (750 ~ 3000 VA), due to its low cost. This equipment consists of a Voltage Regulator, a Transient Suppressor, an AC/DC Battery Charger, a Battery Bank and a DC/AC (Direct Current to Alternating Current) Inverter.
The Interactive UPS, filters the power supplied by the utility; when there is an outage, it automatically turns on the inverter and the power is supplied by the UPS from the batteries with the appropriate voltage and frequency.
As a matter of fact, in this technology, the inverter only turns on when there is an outage and the transfer time (i.e. it is from 2ms to 8ms. To emphasize, normally the output regulation is within ±10 ~15% of the nominal voltage and when operating from the battery, the output regulation is ±5% of the nominal voltage.
It also solves the following electrical problems: Momentary High and Low Voltage, Sustained High and Low Voltage and Power Failure.
On the other hand, the Online UPS is the most used for mission critical applications (those that under no circumstances can stop working and that due to their importance need the highest possible power quality and reliability).
Some examples are: medical equipment on which human lives depend, data centers, financial systems, telecommunications systems, video surveillance, industrial facilities, etc (1 ~ 1000 kVA).
In the same way, it solves the nine most common electrical problems, which are: Momentary High and Low Voltage, Sustained High and Low Voltage, Power Supply Outage/Failure, Electrical Noise, Frequency Variation, Line Transients and Harmonic Distortion.
The On-Line UPS consists of three main blocks: Rectifier (or battery charger), Batteries and Inverter. This process of conversion from Alternating Current (AC) to Direct Current (DC) to Alternating Current (AC) is called “Double Conversion”.
Moreover, in this technology, the inverter remains on all the time, therefore, it generates high quality energy, with stabilized voltages and frequencies, free of impurities and any electrical phenomenon.
The equipment also has an emergency Bypass line, so that in case of damage to the UPS, the equipment can continue to operate without interruption, through the Bypass.
Finally, they are used in equipment extremely sensitive to voltage variations, or that require a very stable power supply, since the output voltage is always maintained with a variation of no more than +/- 1 %.
The following is a comparison of these two technologies in terms of features and design: