SECTION 10 |
Protections
44
The AC output voltage will shut down due to overload and short circuit conditions as
follows:
POWER SURGE CONDITION: When the AC output current tries to exceed around
200% of the rated value, output current limiting is carried out instantly resulting
in drop in the AC output voltage (the drop is proportional to the load impedance).
Surge Power of 200% will, thus, be provided for < 8 ms every half cycle. If this
situation continues for 2 to 2.5 sec Overload Condition is activated.
OVERLOAD CONDITION: If there is a continuous overload of 110% to 115% for 2 to
3 sec, the output voltage will be shut down. Red LED marked “OVERLOAD” (3,
fig 6.1a) will turn ON and buzzer alarm will sound. The Green LED marked “POWER”
(2, fig 6.1a) will continue to be lighted. The unit will be latched in this shut down
condition and will require manual reset.
To reset, switch OFF the unit using the 3-Postion Rocker Swith “ON/OFF/EXT. Switch”,
wait for 3 minutes and then switch ON the unit again. Before switching ON,
determine and remove the cause of overloading.
SHORT CIRCUIT CONDITION: Short circuit condition will be detected when the AC
output voltage drops to 160VAC or lower over a period of around 1 to 1.5 sec.
The AC output voltage will be shut down thereafter.
Red LED marked “OVERLOAD” (3, fig 6.1a) will turn ON, and buzzer alarm will
sound. The Green LED marked “POWER” (2, fig 6.1a) will continue to be lighted.
The unit will be latched in this shut down condition and will require manual reset.
To reset, switch OFF the unit using the 2-Postion Rocker Switch “ON/OFF/EXT.
Switch”, wait for 3 minutes and then switch ON the unit again. Before switching ON,
determine and remove the cause of overloading.
10.2 WARNING ALARM - LOW DC INPUT VOLTAGE
The voltage at the DC input terminals will be lower than the voltage at the battery
terminals due to voltage drop in the battery wires 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 battery wires if the wires are not
thick enough (Please see page 30 “Connection From Batteries To the DC Input Side
Sizing of Cables and Fuses”). If the voltage at the DC input terminals falls below
10.7V ± 0.1V for 12V versions or 21.4V ± 0.2V for 24V versions, a buzzer alarm will
be sounded. The Green LED marked “POWER” (2, fig 6.1a) and indication light
on AC output voltage would 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 in verter terminals further drops to 10V ± 0.1V for 12V
versions or 20V ± 0.2 V for 24V versions.
