Application Guide; I/O Panels; Power Distribution - Lab.gruppen PLM Series Operation Manual

12 APPLICATION GUIDE

12.1 I/O Panels

System interconnection on-site is made quicker and
simpler if racks are prewired internally to connection
panels. If the panels are fitted to the front of the rack,
all audio, loudspeaker, network and power cables may
then be simply plugged in at one position without
requiring access to the rear of the rack.
Rental companies and other large system users will
most likely already have their own preferred designs
for such panels; figure 12-1 is a suggested layout
which others may find useful. This panel is used
purely for audio connections (both AES/EBU and
analog). A separate panel can be used for Ethernet
connections.

12.2 Power Distribution

For professional applications it is recommend that the
sum of the available mains power is above 3000 W
per PLM (e.g. 230 V x 16 A, 120 V x 32 A). Please see
the following examples suggesting power distriibution
methods across multiple PLM devices.
6 x PLM and 230 V mains supply.
If the mains supply is 230 V and the system
requirement is six PLMs, then the mains capacity
would need to be able to provide 3 x 32 A. There are
two methods of achieving this:
▸ Three racks, each with two PLMs and a 32 A
single phase mains supply. The 32 A capacity is
shared between the two PLMs within the rack.
This is beneficial as the two PLMs don't have to
draw the same current. The only limitation is that
in combination they don't draw over 32 A.
▸
Three racks, each with three PLMs and a 16 A
three phase mains supply. This requires central
power distribution to be configured as two 3 x 16
A circuits from 3 x 32 A. One phase is used for
each PLM within the rack. This has the benefit
that each PLM has its own breaker, but they all
have to operate within the same limit of 16 A;
therefore, more care must be taken to ensure that
no breaker blows if different loads are used.
62 PLM Series Operation Manual
6 x PLM and 115 V mains supply.
If the mains supply is 115 V and the system
requirement is 6 PLMs, then the mains capacity
would need to be able to supply two 3 x 30 A circuits.
There are two methods of achieving this:
▸ Two racks, each with three 230 V version PLMs
and a 30 A three phase mains supply. In the rack
the 30 A is shared between the three PLMs. This
has the benefit that the three PLMs don't have
to draw the same current; one can be allowed
to draw a little more than the other two. The
only limitation is that in combination they don't
draw over 30 A.
▸ Two racks, each with three 115 V version PLMs
and a 30 A three phase mains supply. One phase
is used for each PLM within the rack. This has
the benefit that each PLM has its own breaker,
but they all have to operate within the same limit
of 30 A; therefore, more care must be taken to
ensure that no breaker blows if different loads
are used.
All of the examples given will work, although the
first examples for both 230 V and 115 V operation
has a slight advantage due to their "power sharing"
ability.
As the PLM is equipped with PAL, the power supply
will limit its mains current draw (both momentary
current draw and current draw over time) to be <28
A for the 230 V version and <53 A for the 115 V
version.
There is no requirement for approved equipment to
have a fuse as long as it doesn't create a fire under
fault conditions.
The 230 V version of the PLM is equipped with a
slow blow 30 A ceramic fuse.
The 115 V version is equipped with a metal cylinder
instead of a fuse due to suitable fuses at the required
current rating being unavailable.