Knowledge Base

Definition, Selection, seeking advice, Training



What types of topologies are employed in Online UPS configurations?



To satisfy the need of various applications and from the view point of criticality in operation, different methods are applied in Online UPS. The complexity and sophistication increases in ascending order.

Hot standby Online UPS configuration:






This configuration comprises of two units of Online UPS's (named Online UPS 1 & online Online UPS 2). When Online UPS1 is delivering power to the load, Online UPS 2 remains idle. In case of fault in the inverter of Online UPS 1, static switch is enabled thereby providing uninterrupted power to the load through Online UPS 2. Online UPS 1 runs in synchronism with Online UPS 2, assuring no break transfer from Online UPS 1 to Online UPS 2. Under good conditions, the batteries get charged through their corresponding rectifiers.




Parallel redundant Online UPS configuration:






Online UPS 1 & Online UPS 2 is paralleled together through a paralleling unit. The output load is shared equally (50%) by both the Online UPS under healthy conditions. Upon failure of Online UPS 1, the entire load is taken care of by Online UPS 2 & vice versa. The bypass static switch will be enabled only when the both Online UPS systems fail, providing immediate power to load. The batteries are independently charged through their respective rectifiers. Both the Online UPS systems are synchronized with bypass.




Truth Table:







Static Switch


Online UPS 1 & 2 healthy


Load is shared in equal proportion (50%) by both Online UPS.

Online UPS 1 healthy & Online UPS2 trip


Online UPS1 handles entire load

Online UPS 2 healthy & Online UPS1 trip


Online UPS2 handles entire load

Online UPS 1 & 2 trip


Load works on Bypass






Critical non-critical system of Online UPS






Online UPS 1 & Online UPS 2 delivers power to the critical & non-critical loads respectively under healthy conditions. Online UPS 1 synchronizes with Online UPS 2 & Online UPS 2 synchronizes with the bypass. The reconfiguration of the critical inverter will be responsible for retransferring the loads of their corresponding inverters.  In case of a critical inverter failure, critical load works on Online UPS 2 through enabled STSW 1, simultaneously transferring the non-critical load to Bypass by activating STSW 3 & inhibiting STSW 2. The batteries are charged through their corresponding rectifiers. 




Truth Table for Online UPS :











Online UPS 1 & Online UPS 2 healthy




Critical load on Online UPS 1
Non Critical load on Online UPS 2

Online UPS .1 trip & Online UPS 2 healthy




Critical load on Online UPS 2
Non Critical load on Bypass

Online UPS .2 trip & Online UPS 1 healthy




Online UPS 2 handles entire load






Is Online UPS better ?



Online UPS provide great overall power protection to your computers and peripherals. This safety includes power conditioning, regulated voltage and frequency and zero transfer time to battery during mains failure.






How do I install my Online UPS?



Online UPS need to be installed under supervision of a qualified Technician/Engineer. We also provide necessary assistance from our electrical contractor. 
Our supplier and vendors of Online UPS can install it for you.
Note: Never Try to install the Online UPS by yourself because it has some necessary procedure  which you don't know and this is a hi-risk responsibility because lack of technical information due to very high DC voltage (battery), By doing so the warrantee also void.






What After Sales Services of Online UPS?



All Online UPS needs to be serviced every 6 months to ensure its proper operation and battery condition.

We are proud of our reputation for customer service We have a range of maintenance plans to suit every customer requirements from simpler repair to annual service contracts with guaranteed response time. And every customer of this online service has free access to our customer support.






What is Load Crest Factor of Online UPS?



A pure sine waveform has a peak value, which is 1.414 times the RMS value indicated on a voltmeter. A resistance or any linear load connected to such a voltage source draws currents having similar waveforms and hence has a crest factor of 1.4. As against this, the non-linear loads as described above may demand currents whose peak value to RMS ratios are 2 to 5 or more. This ratio of peak to RMS is termed as the crest factor, and is indicative of the degree of non-linear load handling capability of the Online UPS.







What is Static Regulation of Online UPS ?




A regulated voltage source such as inverter section of Online UPS is expected to maintain the voltage at a predefined level, irrespective of changes in supply, 1.e. DC input voltage or load current levels. The percentage deviation of the output, as a result of load or dc input change, after the output voltage has settled to a new level is defined as the static or steady state regulation. 



What is Dynamic or Transient Regulation of Online UPS?



Online UPS have the Dynamic Regulation on Output voltage. The percentage deviation of the output from its steady state value immediately following a disturbance such as sudden change of DC supply voltage or load current is termed as dynamic/transient regulation. This deviation is generally much larger than the steady state value specified as voltage regulation, and incidentally is a measure of the speed of response of inverter control system. Since by definition this is a transient quantity, not only the deviation but the duration to bring the voltage back to steady state regulation level is also an important index of performance.