48System architecture
power" (page 48)). An AC-powered system that does not require long-term backup can benefit from a UPS with short-term backup because the UPS typically provides power conditioning during normal operation, as well as reserve power during short outages or blowouts.
Figure 17
ExternalAC-power architecture with reserve power
DC power
DC-powered systems always require external rectifiers to convert commercial AC power into the standard –48 V DC required within the system (see Figure 18 "ExternalDC-power architecture with reserve power" (page 49)). Batteries are generally used with DC-powered systems, as the traditional telecommunications powering method is for the rectifiers to continuously charge a bank of batteries, while the system power "floats" in parallel on the battery voltage. However, batteries are only required
if reserve power is needed.
A variety of rectifiers and distribution equipment can be used to supply external DC power. Existing customer equipment can be used or a system that Nortel either supplies or recommends, such as the Small or Large Candeo, can be used. The Small Candeo is appropriate for Single Group or Multi Group systems that do not require more than 300 A, while the Large Candeo is suitable for larger systems. In all cases, equipment
for rectification and distribution is required, while reserve batteries are optional.
Nortel Communication Server 1000
Communication Server 1000M and Meridian 1 Large System Overview
NN43021-110 02.05 Standard
30 September 2008
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