Specifications

Mobility and Logistics, Traffic Solutions

Sopers Lane, Poole, Dorset, BH17 7ER

Security classification Unrestricted Page 56 of 83

Version 2 Status Released

Last Editor Harry Smyth Date 09/12/2014

Document Name Configuration Control Document No. 667/CC/45950/000

4.5 Mains Transformer

The appropriate transformer is contained with the Outer case specified in Table 4 and

should not be ordered separately. The mains transformers will occupy a position in the

bottom left hand corner of the controller. Please refer to Figure 39, which shows one

transformer fitted to the ST950ELV cabinet. On those occasions when a 20A variant of the

controller is chosen one transformer and one HPU will be provided, to supply the appropriate

load. When a 40A Outercase is specified an additional transformer and HPU Card will

installed, alongside the first transformer and HPU Card. Individual leads from the transformer

will be connected to SKT 3 on the high power to the HPU Card. A loom from the transformer

will be connected into PL5 on the HPU. On those occasions when a 40A Outercase is

specified the corresponding connection from the second transformer will be connected to the

corresponding connections on the second HPU Card. If a 40A controller has been specified

and therefore a second HPU PCB is fitted a four way relay connection cable will be inserted

between PL1 on the first HPU Card and PL2 on the second HPU Card.

The input voltage to the Dimming Transformer can be selected by connecting the input

supply leads to the appropriate terminals. Please refer to the ST950 General Handbook

Please note that a low Inrush version of the ST950 controller is available. Please refer to

Table 4.

Figure 39 – ST950 HPU and Transformer Figure 40 – SKT3

Mains

Transformer

HPU

SKT 3

HPU

PL5

Earth

Common

Dim

Bright