LEGRAND KEOR T EVO, Installation & Operation Manual

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KEOR T EVO
Installa
tion & Oper
ation M
anual
4. Operation Modes
Uninterruptible Power Supplies (UPS) most important function is the protection of critical and sensitive loads
from the irregular mains voltage conditions. They are used to supply uninterruptible energy to these loads
in such irregular mains voltage conditions and provide regulated energy supply to the equipment present in
the IT room, industrial workshop, hospitals and offices.
KEOR T EVO UPS during Online mode operation provides stable pure sine wave not affected by input voltage
fluctuations. This helps to extend the life time of your sensible loads. Power factor of the current consumed
from mains is nearly one. This allows perfect adaptation to upstream generator or isolation transformer
supply. The reactive power consumption decreases.
During mains voltage failure, the energy needed for the load is provided by the internal battery (or installed
in external battery cabinet/s). These batteries are charged by an intelligent battery charging circuit when
mains voltage is within the limits. Batteries are lead acid battery (VRLA) and do not require any maintenance
until the end of their life time.
In case of long overload or inverter failure situation, UPS transfers the load supply to bypass line, and load is
supplied by mains . When the condition turns back to normal, UPS will continue to supply the load through
inverter.
UPS control and management is done by Digital Signal Processor (DSP) which is 200 times faster than
standard microprocessors. This helps to make your UPS smarter. DSP uses all the sources on optimum
conditions, observes the failure conditions, and communicates with your computer system.
UPS can be operated in one of the following operational modes depending on the condition of mains
voltage, battery, load, UPS status or user preference.
You may see the block diagram of UPS in Appendix-6 Description of UPS and Block Diagram.
4.1. Online Mode
Energy is drawn from the mains voltage input. Loads are supplied through the rectifier and the inverter. The
AC voltage at the input is converted to a DC voltage by the rectifier. The inverter converts this DC voltage to
an AC voltage with a stable sinusoidal waveform, amplitude and frequency. Output voltage and frequency
can be set via front panel. Output voltage is sinusoidal and has a regulated amplitude and frequency. It is
independent from the input voltage. The loads are not affected by the disturbances of the mains voltage.
If the mains voltage and frequency are in an acceptable range, Online Operation is possible.
Check Appendix-4 Technical Specifications for Online Operation mode mains voltage limits.
The upper limit of mains voltage is independent from the load percentage and it is Ph-N: 270V. UPS switches
to Battery Operation mode when the mains voltage is over Ph-N: 270V. The mains voltage is required to
decrease below Ph-N: 260V for UPS to return Online Operation.
Online Operation Conditions;
•
In case Online Operation is set as operation mode of UPS, the mains voltage is within the limits and/or if there
is no abnormal condition (overheat, overload, failure…etc.) UPS operates in Online Operation. Except for
failures, as soon as the abnormal conditions are eliminated, UPS switches to Online Operation automatically.
•
In case Bypass Operation is set as operation mode of UPS and the voltage and frequency is out of the bypass
limits but within the rectifier limits, UPS switches to Online Operation.