Specifications

Mobility and Logistics, Traffic Solutions

Sopers Lane, Poole, Dorset, BH17 7ER

Security classification Unrestricted Page 55 of 83

Version 2 Status Released

Last Editor Harry Smyth Date 09/12/2014

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

4.4 Master Switch Unit

The Master Switch Assembly forms part of the Outercase, chosen from Table 4, and

therefore should not be ordered separately. With reference to Figure 38 the main supply

voltage is applied to the main ON/OFF 63A double pole switch, within the Master Switch

Assembly, for onward supply to the ST900ELV Traffic Controller.

The live connection is taken from the main ON/OFF switch and applied to the 30A controller

fuse unit. The output from the fuse unit is applied to a mains filter, detailed in Figure 38, for

onward distribution, via a dedicated 20A MCB, to the mains transformer.

Additional outputs are taken from the fuse unit and supplied to additional 6A Mini Circuit

Breakers. These additional 6A type C mini circuit breakers provide the controller working

supplies, independent of the main controller power - for example, to cabinet illumination or

Gemini unit or Stratos Outstation.

Neutral distribution is provided from the 63A switch by connecting the neutral output terminal

of the 63A switch to a separate neutral terminal, as shown in Figure 38.

Figure 38 – ST950 Master Switch Assembly

Low Inrush Controller

Please note, the configuration of the master switch unit on the Low Inrush Controller

variants will be different from the Master Switch Unit described above. In particular a 6 Amp

type D MCB will be set in place of the 20A MCB on the Low Inrush controller. It is important

to note that the 6A type C MCBs, used to supply the controller working supplies on the

standard Controller, are not interchangeable with the Low Inrush, main supply, 6A type D

MCB. Please refer to the ST950 General Handbook for further clarification on this point.

6A type C

Mini Circuit

Breakers

Neutral

Terminal

Mains Filter

and 20A MCB

supplying

Mains

Transformer

63A Double

Pole Switch

Controller

fuse unit