Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 12 Page 55 of 265
3.14 Controller Load, Power Consumption and Lamp Supply Transformer
Selection
This section describes the method used to determine that the controller can supply
the total lamp load required, how to select whether one or two lamp supply
transformers are required, and how to determine the overall power used for
estimation of site running costs.
In order to do this, the power taken by the lamps needs to be calculated. Use the
following table to determine the average power taken by the different types of lamps.
Bright
48V
Dim
27.5V
STC ELV Regulatory Sign 7 W -
STC Helios ELV (Vehicular or Far-Side Ped Signals) 12 W 3.5 W
STC LED Wait Indicator (for Far-Side Ped Signals) 7 W 2.5 W
STC Red/Green Nearside Signals 18 W 3 W
STC Ped Demand Indicator (for Near-Side Signals) 6 W 1.2 W
Table 10 – ST900 ELV Lamp Load (Watts)
3.14.1 ELV Controller Load
Typical supply requirement for a controller including lamp supply transformer
(excluding lamp loads, detectors and OTU) is:
 40W for one ELV Transformer and three LSLS cards
 73W for two ELV Transformers and six LSLS cards
Detector power requirements are as follows:
 Siemens ST4R/ST4S detectors require 2.4W per unit.
 Sarasota MTS36Z (2 channel) or MTS38Z (4 channel) detectors require 3W
per unit. (N.B. The power consumption is the same for both 2 and 4 channel
units.)
 Microsense detectors require 6W per unit.