Infrastructure and Mobility, Traffic Solutions
Sopers Lane, Poole, Dorset
BH17 7ER
Version
7
Page 21 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
Figure 5-1 displays a basic estimated battery hold up time chart for all options of the UPS
Solution at nominal ambient temperature of 20°C. Dashed lines indicate the estimated
hold up at 0°C. See APPENDIX A – Estimated Hold Up Times for a clearer view of
battery hold up against ambient temperature.
WARNING:
The chart shown in Figure 5-1 is a performance estimate based on
manufacturer information and is to be used as a sizing guideline only.
Temperature extremes in both the hot and cold regions have detrimental effects on the
performance of the UPS Solution. See section 12.5 for more information on temperature
de-rating.
5.2 Sizing Example
The following subsections give an example of sizing a UPS solution for a traffic
intersection in the UK with the following requirements.
Required Junction Power:
900W
Desired Hold up Time:
3.5 hours
WARNING:
For the majority of UK installations, it is reasonable to assume a
worst case cabinet temperature range of
0°C
to
65°C
.The UPS Solution
must
be derated
to at least these values to help ensure correct operation.
5.2.1 Which UPS Unit Should be Installed?
Derating the UPS units’ power output to the reasonable UK worst case of
65°C
gives the
following maximum output figures:
FXM1100 max. output at 65°C:
962.5W/VA
FXM2000 max. output at 65°C:
1700W/VA
A junction requiring 900W of power falls within the
FXM1100
range.
5.2.2 How Many Battery Packs are Required?
Derating the battery hold up performance to the reasonable UK worst case of
0°C
, two
battery packs
are not
sufficient to support a 900W load for 3.5 hours. Three battery
packs are required. See Figure 5-2 on the following page.
