Specifications

RailCorp Engineering Manual — Signals — Equipment Manual
Cerberus Level Crossing Monitor Field Equipment Manual TMG E1261
© RailCorp Page 59 of 89
Issued August 2012 UNCONTROLLED WHEN PRINTED Version 2.1
The CUT OFF Timer and the TEST CUT OFF Relay are tested by the Level Crossing
Monitor prior to a remote battery test.
The CUT OFF Timer is used as an independent control to prevent a failure of the Level
Crossing Monitor failing the Level Crossing Battery which would be a serious safety risk.
5.1.5 Test Load Resistor
The test resistor is required to draw a test current from the Level Crossing Battery.
Current practice for testing level crossing batteries is to operate the Test Switch for 2
minutes. This runs the crossing with the AC supply disconnected. The Battery voltage is
continually monitored by the Store 74 Alarm card and gives a indication if the battery
voltage falls below a preset level.
A 10 cell level crossing will draw approximately 15A for the duration of the 2 minute test
using the Test Switch box. A 12 cell level crossing draws approximately 23A for the
duration of the test. The equivalent ampere - hour drains on the batteries are 0.5AH for
10 cells and 0.76AH for 12 cells. The remote test of the Level Crossing Battery using the
level crossing monitor should provide a similar load test.
A 1.5 to 1.7Ω resistor is used as the Battery test load. Allowing for losses in wiring the
following maximum currents will be drawn.
Voltage
Number of
cells
Test
Resistance
MAX
Current
Require
d AH
Time
needed
15V 12 cells
1.5Ω
10A 0.76A
280
seconds
12V 10 cells
1.5Ω
8A 0.50A
225
seconds
A remote test duration of 5 minutes was chosen as an adequate test time.
5.2 Equipment Installation
Signalling wiring 7/0.4 should be terminated with red bootlace ferrules. Either a Cable
Accessories BLP 100, a Klippon 901908, a Wago 216-203, or a Phoenix 3200030. The
Cable Accessories HNKE4, and Klippon PZ4 crimp tools are suitable.
The main box is normally secured to the top of the relay rack. It is designed to be
mounted horizontally but may be mounted vertically. Space should be left above the
main box so that the top cover can easily be removed.
Current sensors, VIOs, input optoisolators, and output optoisolator are mounted on DIN
rail. The modem is typically sat on the monitor box. The cables are laid in the cable ducts
and the screw locks at both ends screwed up.
The wire run through the current sensors must be run so that the direction of +ve current
flow is in the direction marked on the current sensor. The current sensors will not work if
the current flow through the sense wire is in the wrong direction.
The battery test load resistor generates a significant amount of heat while a battery test is
being conducted. Therefore space must be left above the resistor so that relays etc
mounted above the resistor are not damaged over time by the heat generated.