User's Manual

10 68P80801H45-1 1/20/2002
Parts and Suppliers EBTS System Manual - Vol 2
Battery System
Connections
The cable loop length refers to the total length of wire within a given circuit. For
example, the combined length of the -48 Vdc (hot) lead and the DC return lead
equals the cable loop length. This would mean that a cabinet that needs 16 feet of
wire between the batteries and Power Supply Rack has a total loop length of
32 feet.
Determining Battery System Wire Size
The wire size for the connection between the batteries and the Power Supply Rack
is determined by the required wire length and the maximum allowable voltage
drop. The voltage drop in the loop must be kept to below 200 mV. The wire
selected should be UL approved and contain a high number of strands
for flexibility.
For a standard configuration, the Power Supply rack is located directly adjacent to
the batteries with a cable loop length of 20 feet or less, which requires the use of a
4/0 wire. Table 3 shows recommended wire sizes for various loop lengths. Larger
wire sizes may be used if the recommended sizes are not available. The
recommended wire sizes are large enough to allow site expansion to a fully
loaded site.
Selecting Battery System Lugs
Depending on the wire size used and the manufacturer of the Batteries, different
wire lugs are crimped onto the power cable ends. After the wire size has been
determined from Table 3, verify the manufacturer of the Batteries (Dynasty
or Absolyte).
Two different battery systems are offered with the EBTS. The Dynasty system is a
low to medium capacity, field expandable system supplied for smaller sites or
sites with minimal backup hour requirements. This system is custom designed to
Motorola specifications. The Dynasty system is manufactured by
Johnson Controls:
Table 3 Battery System Wire Size
Loop Length Wire size
20 feet 4/0 (or 250 MCM)
30 feet 350 MCM
45 feet 500 MCM