APC VS 50 - Manual (Page 26)

Magnum VS –48 Vdc User’s Manual Page 21
System Current Monitor
The controller monitors individual rectifier currents and displays total system current as a sum of
rectifier currents. Load current can be found by adding battery current to system current.
Battery Current is positive when the battery is discharging.
Sys Current + Batt current = Load Current
For example, if the battery is charging the Batt Current reading could be (–) 10 A, Sys Current
reading could be 50 A. Load Current would be:
Sys Current + Batt current = Load Current
50 A + (-) 10 A = 40 A.
If the battery is discharging the Batt Current reading could be 10 A, Sys Current reading could
be 30 A. Load current would be:
Sys Current + Batt current = Load Current
30 A + 10 A = 40 A.
System Status and Alarm Reporting
The controller will monitor system, temperature. The controller reports system high and low
temperature alarms.
5.3. Load Management
Circuit Breakers
Distribution is included for up to 2 circuit breakers or eight GMT fuses per 50-A shelf. The circuit
breakers can be 2 X 30 A or 1 X 60 A in each shelf. The GMT fuses are 8 X ¼ to 15 A in each
shelf. When a circuit breaker trips, a normally open switch closes and the controller reports a
CB alarm. Alarms are reported only when a breaker is tripped. When a breaker is turned off, no
alarm is generated. Circuit Breaker Alm 1 or 2 are reported when a circuit breaker in the top
shelf trips. Circuit Breaker Alm 3 or 4 are reported when a circuit breaker in the bottom shelf
trips. Because of this, if a Magnum VS 100 has GMT fuses in the top shelf and 2 circuit
breakers in the bottom shelf, the circuit breakers will be labeled CB1 & CB2 on the front panel,
but Circuit Breaker Alarm 3 & 4 will be reported. If a Magnum VS 100 has GMT fuses in the top
shelf and 1 circuit breaker in the bottom shelf, the circuit breaker will be labeled CB1 on the front
panel, Circuit Breaker Alarm 3 will be reported. If a Magnum VS 100 has 1 circuit breaker in the
top shelf and 1 circuit breaker in the bottom shelf, the circuit breakers in the bottom shelf will be
labeled CB2 on the front panel, but Circuit Breaker Alarm 3 will be reported. To disconnect a
load attached to a circuit breaker, move the lever down to the “OFF” position.