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P O W E R I N G T E C H N O L O G Y
Document Number: MS0031-MAN rev. 7
guardian_access_ms31-man-rev7-0521.indd
If disconnection occurs, the batteries will be reconnected when mains supply returns.
2.3.2.2 Partial Load Disconnection / Load Shedding (PLD)
Partial load disconnection can be configured to be voltage or time dependent, this is
selected when ordering the power system.
At a mains outage the controller will open the PLD contactor when the batteries
have discharged to a certain voltage or if the battery voltage has been under a certain
voltage for a predetermined time. The disconnection has to be set according to the
present load and battery manufacturer’s discharge tables or requirements.
2.4.3 Rectifier Module
The fan-cooled rectifier converts the AC input to -48VDC output for loads and batteries.
It is designed for parallel operation and plug-in installation in the power shelf and supplies
extremely stable DC power.
Each rectifier incorporates an internal microprocessor that sends frequent updates to the
system controller and adjacent rectifiers. This ensures accurately controlled load sharing
among rectifiers and supplies status and identification information to the controller.
The rectifier module features two LEDs for status indication, thermal protection with
power derating, and input over voltage disconnection with automatic reset. The rectifier
module is hot-swappable and can be quickly removed and replaced without disrupting
the system or load.
Handles
Cooling Fans
Status LEDs
Figure 2-3 Guardian Rectifier
The power system is normally configured with N+1 redundancy, with N as the number
of rectifier modules necessary for feeding the load and charging the battery and 1 as the
redundant rectifier module. In normal operation the rectifier modules are feeding the
load and simultaneously maintaining the batteries in a fully charged state.
