Technical data

7
5 AC/DC Converter
MASTERGUARD Series SIII
UPS Systems from 60 to 800 kVA
MKA4CAT0UKSIII/Rev. 11-11/2004/UK
5.11.2 Automatic Battery Test
The operating condition of the
batteries shall be automatically tested
by the control unit at selectable
intervals, e.g. weekly, fortnightly or
monthly. A short-time discharge of the
battery will be made to confirm that all
the battery blocks and connecting
elements are in good working order. In
order to preclude a faulty diagnosis the
test will be launched 24 hours after the
latest battery discharge at the earliest.
The battery test shall be performed
without any risk to the user, even if the
battery is completely defective. Users
shall be alerted to a detected battery
fault. The battery test shall not cause
any degradation in terms of the battery
system life expectancy.
5.11.3 Ambient Temperature Compensated
Battery Charger
The float voltage and battery discharge
alarm shall be automatically adjusted
as a function of the temperature in the
battery compartment (-0.11% per °C ) in
order to maximise battery operating life.
5.11.4 Time Compensated End Of
Discharge Voltage
When the discharge time exceeds one
hour, the shutdown voltage shall be
automatically increased, as shown in
Figure 4 for VRLA, to avoid heavy battery
discharge as a result of a light load.
5.11.5 Battery Ripple Current (only
for 60-500kVA range)
When batteries are fully charged the
battery care algorithm places them in
stand-by mode, disconnecting them
from the rectifier. This status prevents
charging current ripple and enhance
battery operating life.
5.11.6 Remaining Battery Life
Series S
III uses sophisticated algorithms
to determine the battery life remaining
based on real operating conditions
such as temperature, discharge and
charging cycles, and discharge depth.
5.11 Battery Management
Using advanced battery care (ABC)
Series S
III series shall increase battery
life by up to 50%. The main battery
care features are described below.
5.11.1 Operating Parameters
When operating with a maintenance
free, valve regulated lead acid battery
(VRLA), the parameters per cell shall
be as follows:
• End of discharge voltage (V) 1.65
• Shutdown imminent alarm (V) 1.75
• Minimum battery test voltage (V) 1.9
• Nominal voltage (V) 2.0
•Battery discharging alarm (V) 2.20
@ 20°C
• Float voltage (V) 2.27 @ 20°C
• High voltage alarm (V) 2.4
Figure 4. End-of-discharge voltage in relation to discharge time
1.80
Voltage per cell
Thime (hours)
1.75
1.70
1.65
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Tecnico-SIII-MG 10-11-2004 8:22 Pagina 7