Mobility, Intelligent Traffic Systems
Sopers Lane, Poole, Dorset, BH17 7ER
Copyright © Siemens plc 2020. All Rights Reserved. Mobility is a division of Siemens Plc
4.1.2 Low Inrush Transformer:
Siemens have developed a low inrush transformer that allows lower rating
protection devices to be used, as shown below: -
Controller MCB changed from 20A type D MCB to 6A type D MCB,
Master Fuse changed from 30A to 16A
Electricity Cut-out fuse changed from 45A to 25A.
The lower rating Electricity Cut-out fuse encourages the Electricity Supplier to
provide power without supply metering.
The low inrush transformers are available in 20A only controller cabinets; see the
appendix for Part Numbers.
A low inrush transformer weighs about 20kg. In the very unlikely
event of a transformer failing, appropriate lifting techniques MUST be
used, and leather rigger gloves are recommended.
4.2 High Power Unit (HPU)
The HPU distributes the 48V lamp supply and low voltage logic supply from the
Lamp Supply transformer to three LSLS cards. It has monitor circuitry and
terminations for the connection of up to eight 48V regulatory signs, provides
connections for the Solar Cell and 24V Loop Detector/above ground detector supply
and incorporates the Dim/Bright, A and B relays. If the total lamp load exceeds 20A
or more then three LSLS cards are required, see section 4.3.
The HPU provides the following outputs:
Measures as:
(See Note 1)
SK1 pins 1a, 2a, 3a,
4a, 5a, 6a, 7a, 8a
SK1 pins 1b, 2b, 3b,
4b, 5b, 6b, 7b, 8b
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