PROTECTIONS AGAINST ABNORMAL
CONDITIONS
Page 25
No load draw (idle current)
When the on / off switch is turned on, all the circuitry inside the inverter becomes alive
and the AC output is made available. In this condition, even when no load is being
supplied (or, if a load is connected but has been switched off), the inverter draws a
small amount of current from the batteries to keep the circuitry alive and ready to
deliver the required power on demand. This is called the idle current or the no load
draw. Hence, when the load is not required to be operated, turn off the on / off switch
on the inverter to prevent unnecessary current drain from the battery.
The inverter has been provided with protections detailed below.
Low DC input voltage warning alarm.
The voltage at the DC input terminals will be lower than the voltage at the battery
terminals due to the voltage drop in the battery cables and connectors. The drop in
the voltage at the DC input terminals of the inverter could be due to lower battery
voltage or due to abnormally high drop in the cables if the cables are not thick
enough (Please read under
“Installation – Connection from the batteries to the DC
input side of the inverter – cable and fuse sizes” on page 20
) If the voltage at the DC
input terminals falls below 10.5 V for PST-30S-12A or 21 V for PST-30S-24A, a buzzer
alarm will be sounded. The LED (2) will continue to be green and the AC output
voltage will continue to be available. This warning buzzer alarm indicates that the
battery is running low and that the inverter will be shut down after sometime if the
voltage at the inverter terminals further drops to 10 V for PST-30S-12A or 20 V for PST-
30S-24A.
Shut-down due to low DC input voltage.
If the inverter continues to power the load after the low DC input voltage buzzer
alarm is sounded, it will shut down temporarily when the DC input voltage further
drops below 10 V for PST-30S-12A or 20 V for PST-30S-24A . The LED (2) will turn
orange and there will be no AC output voltage. The buzzer alarm will continue to
sound.
The unit will reset automatically when the voltage of the battery rises to 11.5
V for PST-30S-12A or 23 V for PST-30S-24A .
Shut-down due to high DC input voltage.
If the voltage at the DC input terminals exceeds 16.5 V for PST-30S-12A or 33 V for
PST-30S-24A, the inverter will be shut down temporarily. The LED (2) will turn orange
and there will be no AC output.
The buzzer will be sounded. The unit will be reset
automatically when the voltage drops down to 16.7 +/- 0.2 V for PST-30S-12A or 33.5
V +/- 0.2 for PST-30S-24A .
