Specifications

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2.1.3SIZING THE UPS
2.1.4CONNECTION OF UPS IN PARALLEL
2.1.5OPTIONS AVAILABLE
2.2 COMMUNICATION OPTIONS
2.2.1LOCAL COMMUNICATION
2.2.3REMOTE COMMUNICATION
a
a
bypass
inverter
convertor
AC
DC
AC
AC
DC
AC
manual bypass
static switch
B
A
T
T
E
R
Y
bypass
inverter
convertor
AC
DC
AC
AC
DC
AC
static switch
B
A
T
T
E
R
Y
output
mains
manual bypass
When calculating size of the UPS, it is important to
take into account the following parameters:
• Apparent power (VA or kVA).This is defined as
S=UxI for single-phase loads, S=(ULI x
ILI)+(UL2xIL2)+(UL3xIL3) for three-phase loads
where is the voltage, I is the current absorbed by
the load under normal operating conditions
(EN50091-1-1). This information can usually be
found in the documents and/or data accompanying
the equipment, although it may well be overestimated.
• Active power (W or W). Is defined as P=SxFP where
FP is the power factor. If the value of P and FP of
the loads is not specified, the power absorbed
must be precisely measured in order to select the
right UPS. The typical load of a computer is associated
with an FP of between 0.65 and 0.8. The active power is
particularly important for sizing the batteries.
• Overloads. Overloads are temporary demands from
the equipment that exceed permanent steady
state absorption values. These are caused by cur-
rent peaks that may occur when one or more appli-
ances are started.
• Expansion of the system. When sizing the UPS, fu-
ture power extensions must also be considered. In
any case, the power of the UPS should always ex-
ceed that of the loads to be powered. (Usually a
30% oversizing is recommended).
• Particular consumers. At power-on, some loads are
characterized by much higher than rated absorp-
tion even though for a very short time (from 50 to
100ms). This is the case, for example, of laser
printers, some types of lights, isolation trans-
formers, pumps. For loads of this type, it is good
practice to oversize the UPS (from 3 to 4 times ac-
cording to the type load and the UPS selected).
When in doubt, or if the absorption parameters of
the equipment are not fully known, consult us for
correct sizing indications.
In medium and high level power installations, various
UPS can be connected in parallel:
• to obtain a power supply higher than that of the
individual appliance;
• to improve power supply reliability, guaranteeing
redundancy.
Connecting UPS in parallel makes it possible to in-
crease the power of the back-up system, even after
the first UPS has been installed, or to produce solu-
tions that optimize reliability or simplify use and
maintenance of the system.
The standard version of the UPS can be improved by
adding the following options designed to meet spe-
cific customer needs:
A) SEPARATION TRANSFORMER
The UPS can be used without a galvanic isolation
transformer, maintaining the neutral arrange-
ments between input and output unchanged.
However, in particular cases, a transformer
module can be installed to change the down-
stream neutral arrangements from those up-
stream.
B) SOLUTIONS FOR REDUCING INPUT HARMONIC CURRENTS
There are various solutions for reducing the har-
monic distortion of the input current. For
compliance with standards, some UPS models
(usually in the single/single-phase up to 10kVA
version) are characterized by standard sinusoi-
dal absorption.
For three/single-phase or three-phase UPS's, the
user can select the standard version or one with low
level distortion. The low distortion version should be
selected only if the power of the upstream genera-
tor is similar to that of the UPS (for example, if
there is a 20kVA generator upstream powering a
20kVA UPS). Otherwise, it is advisable to choose the
classical UPS with higher efficiency and lower main-
tenance costs.
• INDICATOR LAMPS
The simple indicator light on the front panel con-
veys immediately the status of the UPS and is usu-
ally sufficient for small size UPS.
• ALPHANUMERIC DISPLAY
For specific information about UPS operating con-
ditions and electrical parameters, it may be useful
to equip the UPS with an alphanumeric display so
that the information provided is absolutely clear.
It also makes it possible to access particular func-
tions tied to use and diagnostics of the UPS.
• REMOTE COMMUNICATION USING SIGNAL CONTACTS If
the UPS is not readily accessible to the operator,
remote signaling may be provided for remote diag-
nostic of the main operating conditions (at least
“general alarm” and “battery operation”). These
signals can be sent to the computer systems pow-
ered by the UPS, to a signal panel at the cus-
tomer's or to a control panel supplied with the
UPS.
• UPS/USER COMMUNICATION
Using zero-potential contacts or a serial communi-
cation line, the UPS can be interfaced with the
protected IT equipment for automatic manage-
ment of system file shutdown in the event of a
blackout and to send operators information about
UPS status.
• SERIAL COMMUNICATION
For a more detailed remote diagnostic of the UPS,
the information can be displayed on an alphanu-
meric panel or directly on a PC. In these cases,
communication tales place on a standard RS232,
RS422 or RS485 serial line, permitting complete