User's Manual

800MHz & VHF Cell Enhancers
Maintenance Handbook
H/book Number:-50-078001HBKM
Issue No:-
A
Date:-02/09/2004
Page:-
79 of 88
5.26 12V Low Voltage Battery Disconnect Module (80-061003)
5.26.1 Description
The low voltage disconnect module’s main function is to monitor the battery voltage as
the batteries discharge. When a pre-set value has been reached (usually 21.5V DC) the
unit will disconnect the batteries to prevent a ‘deep discharge’ state which, if allowed to
continue, could irreparably damage the batteries, necessitating replacement. The unit’s
other function is to regulate the battery voltage to the cell enhancer equipment to 23.5V
when in back-up mode (the terminal voltage of fully charged batteries is likely to be
higher than 27V, and therefore potentially damaging to electronics in the system).
5.26.2 Technical Specification
PARAMETER SPECIFICATION
Operating voltage: 9-16V
Low voltage cut-off point: 10.5V (factory set)
operation: -10°C to +55°C Temperature
range
storage: -20°C to +70°C
Weight: <1kg
Size: 109.98 x 55.88mm
5.27 Crystal Filters (93-980109)
5.27.1 Description
Crystal filters are fitted at the inputs and outputs of the simplex/duplex shelves (instead of
bandpass filters) in order to maximise the excellent isolation and rejection characteristics of
these narrow-band devices. It is easier to achieve close channel spacing using crystal filters,
however, due to the increased insertion losses, higher gain amplification is needed when
they are utilised.
5.28 IXFN170N10 Power Mos-Fet Module (94-030015)
5.28.1 Description
This power module is simply a power MOS-FET transistor which is the series regulator for
the main 24V DC battery output voltage rail. It is enabled/disabled from the discriminator
module, (see section 5.2) has fast switch-off characteristics and a low forward volt drop. It is
attached to a heatsink assembly mounted on the side of the case.