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SECTION 3 |
or the "Idle Power" or "Self Power Consumption" (We will call this as the
"No Load Power Draw"). If the unit is on and is not powering any load,
this "No Load Power Draw" is wasted as it unnecessarily drains the battery
and hence, should be minimized, if possible. The "No Load Power Draw"
of these units in the Normal Mode is around 35W to 45W. This unit has a
provision to minimize this "No Load Power Draw", if required (Applicable
only when the unit is in "Inverter Mode"). This is achieved by enabling
the "Power Save Mode". When "Power Save Mode" is enabled, the unit
does not provide continuous output power but discontinuous and pulsing
output power consisting of only 2 to 3 cycles of reduced 40 vAC output
voltage that are made available every 2.8 seconds and are used to sense
if a minimum load is present or not. As continuous power is not being
supplied, the "No Load Power Draw" is reduced to less than 5W. If a load
> 60W is sensed, the unit exits Power Save Mode and starts providing
normal continuous output power (will now consume the full 35W to 45W
of "No Load Power Draw" of the Normal Mode in addition to the power
consumed by the load). If the load drops to <10W, the unit once again
reverts to Power Save Mode.
When the unit is operating in Power Save Mode, the Green Status
LED (3, Fig 2.3) on the LCD Control Panel blinks @ 4sec. Please read
section 8 - Operation, page 55 for activation and deactivation of
Power save Mode.
Power Save Mode should be disabled for the following loads:
• Low power loads that draw < 60W e.g. digital clocks, satellite
receivers, phones / answering machines etc.
• Audio / video / computing devices that consume normal operating
power > 60 W but draw less than 10W on entering Sleep Mode when
switched off or when no activity is seen for a specified time
Power Save Mode - Transfer Characteristics
in Utility / Generator Mode
Transfer from Utility / Generator: If qualified Utility or Generator
AC input power is available (its voltage and frequency are within the
programmed range), the Transfer Relay remains energized and the AC
input power is passed through to the load and at the same time, the unit
operates as a battery charger. If AC input power from Utility / Generator
fails or is not qualified (its voltage and frequency are not within the
programmed range), the Transfer Relay is de-energized and the load is
transferred to the inverter. When this transfer takes place, the inverter
initially operates in Normal Mode. If the AC load was > 60W, the inverter
continues in Normal Mode. However, if it does not see a load > 60W for
around 5 sec, it enters Power Save Mode.
Transfer from Inverter to Utility / Generator: As soon as AC input
power from Utility / Generator is available, the inverter will exit Power Save
Mode and will switch over to Normal Mode. This switch over is necessary
for synchronizing the AC output of the inverter with the AC input before
transfer (Synchronization can not be carried out with pulsing wave form
during Power Save Mode). Transfer to Utility / Generator is completed after
qualification and synchronization.
Temperature Sensor for battery Charging
Battery Temperature Sensor Model BTS-G4 (Fig 2.4, page 8) has been
provided to ensure optimum charging by modifying the charging
voltages based on temperature if the battery sees very wide temperature
General description &
Principles of Operation
swings. Without temperature compensation, the battery life is likely to
be drastically reduced because the battery will be undercharged during
cold conditions (will build up sulfation) or will be overcharged during hot
conditions (will boil and lose excessive water). Please read white Paper
titled "Batteries, Chargers & alternators" available online at www.
samlexamerica.com (Home > support > white Papers) and section 4
titled "Battery Charging in g4 series" for more details.
Parallel operation With external Charger
The Battery Charger Section is able to operate in parallel with another
external charging source like Solar Charge Controller / AC charger with
a charging capacity of up to 50 A. The output of the external charging
source is routed through this unit and operates in parallel with the internal
charger. The internal charging current is controlled to ensure that the
combined current fed to the battery does not exceed the programmed
Bulk Charging Current. This improves the life of the battery. Please read
more details under "benefits 8" on page 12.
Cooling by Temperature /
Load Controlled Fans.
The unit is cooled by convection and by forced air ventilation by 2
temperature / load controlled fans. One fan (8, Fig 2.1, page 8) near the
DC input connectors sucks air from outside and discharges it inside the
unit. A second internal fan sucks additional air from the mesh protected
ventilation openings on the sides of the top cover (towards the DC input
side) and discharges through the mesh-protected openings on the sides
and the bottom (towards the AC output side). Logic for operation of the
fans is given in Table 3.1 below:
Table 3.1
Logic for operation of Cooling Fans
Controlling
Parameter
Operational Condition of the Fan
Heat Sink
•
Above 65°C, the fan switches on at 50%
Temperature
speed. The fan switches off when cooled
below 50°C
•
At 85°C, fan speed rises to 100%. The fan
speed drops to 50% when cooled to 70°C
Charging Current
•
At more than 25% of maximum charging
in Utility /
current, the fan switches on at 50% speed
Generator Mode
and switches off when in standby
•
At more than 50% of maximum charging
current, the fan speed rises to 100%.
When charging current drops to 40% of
maximum charging current, the fan speed
reduces to 50%
% of load in
•
At 30% load, fan switches on at 50%
Inverter Mode
speed. The fan switches off when load
reduces to 20%
•
At 50% load, the fan speed rises to 100%.
The fan speed drops to 50% when load
reduces to 40%
SAMLEX AMERICA INC. | 11
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