3 Operation
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Alpha Technologies
3.5 Controlling the Unit With the Standard Interface Device (SID)
The Standard Interface Device (SID) display panel (Figure 3.2) shows vital operating param-
eters and starts the self test. It has two push buttons, five LEDs showing the power drawn by the
loads and six LEDs showing the unit’s operating status.
LEDs
Line Present
This green LED is:
• On when the unit is running on line power.
• Off when there is no line power.
• Flashing when line power is present but unqualified.
Line Failure
This yellow LED is on when:
• The line voltage is greater than 10 % or less than 20% of nominal voltage.
• The line frequency is outside of ± 3Hz of the nominal frequency.
• The unit is providing backup battery power to the loads.
TIP:
Also see Low Battery Warning and Low Battery Shutdown.
Low Battery Warning
This red LED turns on when the battery voltage is 8% below nominal. This shows the
batteries are almost discharged and a shutdown is pending. You should start turning off
the loads.
ALARM
OFF
MANUAL
START
OUTPUT LOAD
OVERLOAD
100%
75%
50%
25%
LINE PRESENT
LINE FAILURE
SERVICE
LOW BATTERY
WARNING
LOW BATTERY
SHUTDOWN
TEST
Figure 3.2
Standard Interface Device Display Panel
