GE Industrial Solutions Galaxy Manager - Manual (Page 32)

Galaxy Manager
3 - 18 User Screens Issue 4.3 Preliminary January 2004
Hours to 95%
Recharge
Calculated number of hours to charge completely discharged system
batteries back to 95% capacity. This is a conservative number since the
recharge algorithm is based on an end-cell voltage of 1.75V. If the
recharge time is between 24 and 28.8 hours the displayed recharge time
value will be highlighted yellow. If the recharge time is greater than 28.8
hours the displayed recharge time value will be highlighted red. This is
based on a standard 24-hour recharge time.
Rectifier Recharge
Factor
Calculated ratio of rectifier capacity divided by system load.
Cable Sizing Calculator
The Cable Sizing Calculator provides a pictorial view of the major
elements of the DC distribution network. This calculator is for sizing
cable and assumes that sufficient battery strings are in place to support
the load shown, for the required reserve time, to the minimum discharge
volts per cell that is inputted. Battery voltage at the end of this reserve
period will be the number of cells multiplied by the minimum volts per
cell (VPC). The voltage drops throughout the network may then be
specified and the conductors required to support the load to those
voltage drops, and ultimately to a required minimum voltage at the end
equipment, are calculated.
The voltage drop calculation formula for copper conductors is:
Vdrop = 11.1 x Length (ft) x Load (amps) / cable size (circular mills)
Cable sizes are expressed in standard DC conductor sizes (or their
multiples) available through Lineage Power as follows: 14 AWG, 12
AWG, 10 AWG, 8 AWG, 6 AWG, 4 AWG, 2 AWG, 0 AWG, 00 AWG,
0000 AWG, 350 kcmil, 500 kcmil, and 750 kcmil. All conductor lengths
used in the tool should be entered as one-way cable run lengths and that
the negligible voltage drops of any monitoring shunts, fuses, lug
terminations, etc., within the distribution system have been ignored.
Two Cable Sizing Calculators are provided, one for power systems
using centralized architecture (containing a central bus work where all
load current is monitored using one common shunt or Hall-effect
assembly) and one for distributed architecture systems (no common
load shunt, but with individual rectifier and battery currents monitored).
The centralized calculator is displayed by default. Links are provided at
the top of each calculator (“switch to distributed” and “switch to
centralized”) to change the currently displayed calculator.