Emergency Power Supply 48 Volt; Grounding And Earth Loops; Input Connections; Music Input - Philips SQ 45 User Manual

A replacement plug must be wired as follows:
earth - green/yellow
neutral - blue
live - brown
WARNING:
This apparatus must be earthed.

2.2 Emergency power supply 48 Volt

In situations where the mains power supply
is unreliable an emergency 48 V battery
supply may be used. This supply will
automatically be switched in whenever the
mains power fails. A Mate-N-Lok supply
socket is provided to allow the 48 V DC
battery supply to be connected (fig. 2.12).
Details of the connector are shown in fig. 5
and should be wired accordingly. For use in
special applications, a manual on-off switch
can be connected enabling the 48 V DC
power supply to be switched on and off as
and when required.
The value of the 48 V DC fuse (fig. 3.1) is
10 amp.

2.3 Grounding and earth loops

On delivery the electrical and mechanical
earths of the unit are interconnected. When
two or more units are used in a system, it is
necessary to ensure that earth loops are not
introduced by earth wiring. In this case, the
electrical earths of all units should be linked
together via e.g. points 2 of DIN connector,
then joined by one wire link to the
mechanical earth on one unit only. To
disconnect the electrical and mechanical
earths, jumper S1 (fig. 3.2) must be
positioned as shown or removed.

2.4 Input connections

Each of the amplifiers in the unit is provided
with three inputs: 'priority', 'music' and 'test'.
The connections for these inputs, and the
wiring for the remotely controlled selection
between the 'priority' and the 'music' input,
is made via two, 5-pole 180° DIN-type
sockets per amplifier.
The pins of the corresponding plugs (fig. 6)
are to be connected as described next:
2.5 Music input (fig. 6)
pin 1 - music signal, live
pin 2 - music signal, screen
pin 3 - music signal, live (return)
pin 4 - not connected
Pin 5 - input selection*
* To allow remote control of input signal
selection:
Music input - pins 2 & 5 linked
(relay activated)
Priority input - pins 2 & 5 open
2.6 Priority and Test input (fig. 6)
pin 1 - call signal, live
pin 2 - call signal, screen
pin 3 - call signal, live (return)
pin 4 - test signal, live
pin 5 - test signal, live (return)
The 'test' input (pins 4 and 5) is active under
both conditions.
NOTE:
The 'test' input is provided for ultimate use
with the SM 40 microcomputer controlled
surveillance system.
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