Power Processing System

The power processing system delivers conditioned AC output power with a low distortion sinewave. Under normal operat- ing conditions, power is received from the AC mains (utility) power source, conditioned by the power processing system, and delivered to the load equipment. In the event of an AC mains power source failure, the power processing system re- ceives power from the battery source (battery modules), con- verts it to conditioned AC, and delivers it to the load equip- ment. When AC mains power is present, the power processing system also maintains the battery source at full charge.

The power processing system in SymmetraTM is comprised of one or more power modules. Each power module contains the electronic components for a complete 4kVA UPS,including the rectifier, charger and inverter. When two or more power modules are present, they operate in parallel, sharing the load equally.

By configuring the system with at least one more power mod- ule than is required to power the load (a redundant power module), SymmetraTM can sustain a power module failure and still deliver full power to the load equipment. The failed module is identified by the control/user interface system, an alarm is initiated to notify the user of the module failure, and the hot-swappable module can be replaced by the user, with- out the need to power down the load equipment.

A SymmetraTM MiniFrame provides bays for up to three power modules, and a MasterFrame provides bays for up to five. This provides the full system capacity (8kVA and 16kVA re- spectively), plus one redundant power module.

Battery Source

The battery source is comprised of parallel, hot-swappable, 120V battery modules. These are housed in the SymmetraTM frame, and in an optional XR Extension Battery frame.

A SymmetraTM MiniFrame provides bays for up to two bat- tery modules, and a MasterFrame provides bays for up to four. Both of these frames can be connected to an XR Exten- sion Battery frame. Additional battery modules increase on- battery run time.

Control/User Interface

The control/user interface system coordinates the operation of the SymmetraTM and reports status conditions via several user interface options. Functions performed by the control/ user interface component include module coordination and state control, analysis and reporting of system status, and reporting of alarm conditions.

Module Coordination & State Control - The SymmetraTM incorporates a main intelligence module (MIM) that continu- ously monitors the system, and delivers data to both the PowerView user interface, and to the communication ports. The MIM coordinates the initial power up of the system, trans- fers it into and out of bypass mode, transfers the power source between the mains AC power, and the battery source, and coordinates shutdown operations.

System Status Monitoring - The MIM gathers data about the system components and delivers it to both the PowerView interface, and to the computer interface ports. System status monitoring and reporting data include the current predicted run time, the status of individual battery and power modules, the input & output voltage, input & output voltage frequency, and the size and status of the output load.

Alarm Condition Detection - The control/user interface sys- tem monitors the SymmetraTM for alarm conditions. If an alarm condition is detected, the PowerView user interface ini- tiates an audible and visual alarm. Alarm conditions include on-battery, low battery, module faults, overloads, loss of re- dundancy and a variety of other default and user defined events. All possible alarm messages and the appropriate user responses are provided in Chapter 9.