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adt-audio
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SRC
For fail-safe operation a second, identical power supply and an additional
crossover device are used. See the chapter below for details.
1.2 Power supply installation
The Installation of Power Supply
Units for BC3 Broadcast Mixers
Even though the installation of the power supply devices of the
SRC51 Console is not critical, some important issues have to be
considered to prevent unnecessary problems and to ensure a
problem free operation of the entire system.
Thermal Considerations
Since all power supply devices of the SRC51 console do not necessarily
need forced ventilation, special care must be taken in regards to the
airflow with the installation of the units. The major part of the heat
exchange takes place at the heat sinks mounted on both sides of the
power supply unit. It is crucial that cold air can pass along the heat sink
unimpeded. Air inlets should be placed below the unit, underneath the
heat sink and corresponding air outlets have to be located above the
heat sinks. If the units are mounted in a rack, this might be a problem,
even more if additional devices with high heat dissipation are mounted
in the same rack. The best way to avoid problems due to inappropriate
heat removal is to leave an appropriate free space of 2 or 3 rack spaces
between the particular devices. In addition, no unit should be installed at
the extreme bottom of the rack. To force good distribution of cold air, it is
a good practice to leave 3 rack spaces free at the bottom of the rack.
If the power supply unit is not installed in a rack but used stand-alone on
the floor, care must be taken, that there is at least 5 cm / 2” of free space
between the bottom of the unit and the floor. If this space is to small or
even not existing, air cannot pass thru the device from bottom to top. This
causes limited heat dissipation and might considerably reduce the capacity
of the power supply unit. Spacers are available for this purpose; a wooden
slat of about 5 cm / 2” height is a sufficient solution as well. A higher
distance to the ground is even better, of course. If the unit is placed next
to a wall or in a corner, we recommend, that the distance to any wall is at
least 5 cm / 2”. This rule is also valid for an additional cover plate above
the unit. We recommend that you use such a plate to prevent conductive
parts, pieces of wires, aluminum foils or any other conductive material to
fall into the device thru the slotted cover sheet of the unit. If you use a
cover plate, take care that the distance between the top of the unit and
the additional cover plate is at least 5 cm / 2”.
If the circumstances at the place of installation do not allow applying the
principles listed above, there are a couple of ways to ensure trouble free
installation even though.
Rack-mounted Fan(s)
Installing and using rack-mounted fans is a good decision, if other devices
with a high heat emission are installed in the same rack as the power
supply unit. One or two fan units can be used. If one unit is used, it should
be mounted at the top of the rack. The direction of the fans must transport
hot air out of the rack. Adding a second fan would improve the airflow
even more. This second unit should be installed on the bottom of the rack
in a way, that it blows cold air into the rack. It is a good idea to use a fan
unit with an integrated dust filter. The filter will decrease the dust pollution
in the rack. However, a filter requires continuous maintenance.
Like all fan-cooled systems, the reliability of the cooled devices depends
on the reliability of the fans. If the fans fail, the entire system will fall.
The best way to make sure that a fan cooled system is safe to operate, is
to install at least twice the number of fans that are necessary for normal
operation. This principle ensures that a failure of one or two fans will not
cause total failure.
Fans in the Power Supply Unit
Internal fans are installed in all power supply units for the SRC51
Consoles. Power supply units with fans require free airflow at the rear side
of the unit. If the installation does not cater for the free expulsion of the
hot air, the fan is almost pointless. However, if free airflow is possible, the
heat sink temperature will be reduced from 10 to 20 degrees. The cooling
effect of external, rack-mounted, fan units is even higher. If at all possible,
these units should be used if airflow is blocked by the installation. Since
any fan produces noise the power supply should not be installed in the
control room. Due to the noise, you can usually not use fans if the power
supply unit is installed in the control room.
High capacity Power Supply Unit
In principle, a power supply unit with a higher capacity reduces the
