OnLine Power Signal Saver IPC - Manual (Page 13)

6002-1842 Rev A ECO# 8881
3
1.1 DESCRIPTION
Purpose: Describes the operation of Online Power Battery Backup system. (Figures 1.1,1.2,1.3)
Theory of Operation:
The BBS provides backup power to traffic control and signal equipment
when the utility line out of range or absent all together.
• It consists of the following: (Refer to Figure 1.1 for detail)
UPS controller unit
Battery charger
Microprocessor board
Display board
Monitoring board
• MBS/PTR (Maintenance By-pass Switch/Power Transfer Relay).
• Batteries
The BBS operates as an offline UPS, to supply AC power to a Critical Load when the MBS
is in the BBS position, while charging the batteries at the same time.
It converts DC power from batteries to usable 120VAC 60Hz power.
When external or utility power is present and within range, the BBS remains in a charging mode.
When the external or utility power is out of range (98VAC to132VAC), or absent, the unit will switch
to the BBS mode and provides power to the intersection without interruption. When the utility
power is present or within range, the BBS transfers to utility power and stand-by mode to charge
the batteries.
When the MBS is on the BBS position, the input power supplies AC voltage directly to
Critical load. When the input voltage is out of the operating range (98VAC to 132VAC), which is set
by a microprocessor, the inverter supplies AC output to the critical load within a maximum 65
milliseconds transfer time. Battery run time in this mode will last for minimum of 2 hours at;1500
watt load.
When the input voltage has recovered to the normal Range (105V t o125V
± 2V) and has
been stable for 30 second, the inverter will automatically transfer back to utility power to support
the critical load within maximum of 65-milliseconds.
The Power Transfer Relay continuously monitors line voltage. When the voltage is out of range, a
transfer to inverter power takes place.
The BBS provides remote sensing through a DB9 connector and 3 sets of contactors
available on a panel mount terminal block.The first set of NO and NC contacts are energized when
the unit switches to Battery Power.The second set of NO and NC contacts are energized when the
battery approaches approximately 40% of remaining useful capacity. The third set of NO and NC
contacts are energized 2 hours after the unit switches to battery power.The MBS will allow the BBS
to be removed from the circuit for anything requiring attention such as battery replacement or other
installation requirements.