Installing the Network Gateway Unit
(Continued)
9
NGU Electrical Specifications
Input Rating when used with external PSU:
Input voltage:
22V - 28Vdc
Maximum current consumption: 100mA
Input Rating when used with PSU3A:
Voltage, frequency:
230Vac, ±15%, 50/60Hz
Maximum current consumption: 1.6A (Protection by 2A mains supply fuse in terminal block)
Output Rating when used with PSU3A:
Output voltage:
26V - 28Vdc
Maximum output current:
500mA (with battery charger available) or 2A (without
battery charger), dependent upon the fuse fitted
Battery Charger Output Ratings (PSU3A):
Battery voltage when charged:
27.3V at 20°C (Charge float voltage)
Temperature compensation:
-3mV/°C/cell
Battery fuse rating:
T 6.3A H 250V
Final end battery voltage:
21V
Charger ripple voltage:
140mV RMS
NGU Electrical Specifications
Input Rating when used with external PSU:
Input Rating when used with PSU3A:
Output Rating when used with PSU3A:
Battery Charger Output Ratings (PSU3A):
Input voltage:
22V - 28Vdc
Maximum current consumption: 100mA
Voltage, frequency:
230Vac, ±15%, 50/60Hz
Maximum current consumption: 1.6A (Protection by 2A mains supply fuse in terminal block)
Output voltage:
26V - 28Vdc
Maximum output current:
500mA (with battery charger available) or 2A (without
battery charger), dependent upon the fuse fitted
Battery voltage when charged:
27.3V at 20°C (Charge float voltage)
Temperature compensation:
-3mV/°C/cell
Battery fuse rating:
T 6.3A H 250V
Final end battery voltage:
21V
Charger ripple voltage:
140mV RMS
Low Voltage Shut Down
If the battery voltage drops below 21V, then the batteries are disconnected automatically to avoid system
malfunction and deep discharge causing permanent damage. Battery capacity should be selected to ensure
sufficient backup time in the event of mains power failure.
Battery Capacity
Sealed valve regulated lead-acid battery types MUST be used. Battery lifetime depends on the ambient
temperature. Refer to the battery manufacturer's technical specification for guidance. When using multiple
batteries, all batteries should be from the same Manufacturer, of the same type and date code and be mounted
in the same cabinet.
Two 12V batteries must be connected in series.
Low Voltage Shut Down
Battery Capacity
If the battery voltage drops below 21V, then the batteries are disconnected automatically to avoid system
malfunction and deep discharge causing permanent damage. Battery capacity should be selected to ensure
sufficient backup time in the event of mains power failure.
Sealed valve regulated lead-acid battery types MUST be used. Battery lifetime depends on the ambient
temperature. Refer to the battery manufacturer's technical specification for guidance. When using multiple
batteries, all batteries should be from the same Manufacturer, of the same type and date code and be mounted
in the same cabinet.
Two 12V batteries must be connected in series.
997-451, Issue 6 July 2006
