General Information on Track Circuits - RGS Online

<strong>General</strong> <strong>Information</strong> on Track Circuits
15 Impedance Bonds
Manufacturer Style Freq.
(Hz)
Howells or
WBS
Howells or
WBS
Railway Group Approved Code of Practice
GK/RC0752
Issue Two
Date December 1998
Page E25 of 52
15.1 Handling Precautions
When transporting impedance bonds, they should be lifted only by the lifting lugs
or at the defined lifting points. Under no circumstances should any weight be
taken on the traction lead terminals or cable lugs as this can result in damage to
the insulation, allowing water to enter.
Type 3 impedance bonds have positions for lifting lugs to be fitted, which should
be removed as soon as the impedance bond has been placed in the track and
replaced with the supplied means of protecting the threads.
15.2 Impedance Bond Types and Restrictions
Refer to the table in Figure E22
Function Type Cat No Oil
Filled
Aux. Coil
Ratio
Weight
(Kg)
Supply
WH3 50 Universal 3 86/17024 No 56: 1 160 N
MR or
S
50 Universal 2 86/17023 No 56:1 160 O
WBS P3 50 Universal 1 88/1237 Yes 45:1 S
SGE DE 50 Universal I 88/83945 Yes 40:1 120 S
WBS M 50/75 Specific 0 Yes 42:1 230 O
WBS M2/5 50/75 Specific* 0 88/83948 Yes 42:1 190 S
WBS M650/
75
Withdrawn Document
Uncontrolled When Printed
Specific 0 88/83952 Yes 45:1 230 O
SGE DD 50 Universal 0 Yes 42:1 230 O
GRS B 50 Specific 0 Yes 45:1 O
Figure E22
The table in Figure E22 is interpreted as follows:
Function
Universal
Impedance bonds shown as ”Universal” may be used for all functions in all
styles of track circuit approved for use in d.c. electric traction areas,
subject only to their ability to cope with the designed traction current load.
Note: Saturation levels and avoidance of particular combinations of bond
and track relay, should be considered when replacing bonds of one style
with another (see Clause 15.4).
The impedance bonds are tuned to 50Hz. For other frequencies, internal
resonating capacitors are fitted.
Specific
Impedance bonds shown as ”Specific” are specially set or tuned to perform
feed, relay or intermediate functions at a particular frequency. If, in an
emergency, an impedance bond is required to perform a different function
or operate at the other frequency, it should be re–tuned.
R A I L T R A C K E 25