Infrastructure and Mobility, Traffic Solutions
Sopers Lane, Poole, Dorset
BH17 7ER
Version
7
Page 20 of 76
Status
ISSUED
Last Editor
Ore Oluwatudimu
TS008468
Date
31/01/2017
Document
Name
UPS Solution General Handbook
Doc. No.
667/HB/47750/000
Copyright
Siemens plc 2017 All Rights Reserved
5 Sizing the UPS Solution
5.1 Key Considerations
There are two key factors to consider when sizing a UPS Solution for any one traffic
intersection. These are the
junction power requirements
and the
desired battery hold
up time
.
A traffic intersection’s power requirements determine which of two Alpha FXM UPS units
is to be installed. The required battery support hold up time determines the number of
battery packs that will need to be installed within the UPS Solution. Extended hold up
periods will require the installation of a Battery Expansion Cabinet alongside the UPS
Cabinet.
Where cost or space is critical, a compromise between the junction power requirements
and required hold up time must be reached. Reducing the required hold up time
potentially decreases the number of battery packs to be installed. Reducing the junction
power requirements, and therefore the UPS system output, will allow each battery pack
to go further in terms of hold up time. Both options should be considered to meet
installation requirements.
Figure 5-1: Battery Hold up times at 20°C and 0°C
