Cooling; Operating Voltage - Lab.gruppen PLM series Operation Manual

5.4 Cooling

The PLM uses a forced-air cooling system with airflow from front to rear, allowing high continuous power
levels without thermal problems. (Front-to-rear airflow is preferable as air at the front of a rack is cooler
than that at the rear in nearly all situations.) Never attempt to reverse the airflow. The operation of the
PLM's cooling system is dependent on front-to-rear airflow; it will not function effectively with airflow in the
opposite direction.
Make sure an adequate air supply is provided in front of the PLM, and that the rear of the PLM has sufficient
space to allow the exit air to escape. If the PLM is rack-mounted, never operate the unit with any front or
rear rack doors or covers in position. Also note that any unused rack spaces should have solid blanks fitted
(not ventilation blanks) to ensure efficient air circulation. Leaving gaps in between items of equipment
degrades the effectiveness of forced-air cooling.
If installing one or more PLM units in a rack with other fan-cooled equipment, be sure that all the other units
also use front-to-rear airflow for cooling. If this precaution is not observed, there is a risk of overheating, as
units with the reverse airflow will be drawing in air which has already been heated by the PLMs.
The PLM is equipped with a sophisticated tempera-
ture sensing system which protects it from any
overheating which may occur as a result of
inadequate ventillation. Should a power output
channel overheat, the temperature sensing circuits will mute
that channel until the temperature reduces to a safe level. If the
power supply overheats, another sensing circuit will mute will
reduce the overall output level of all channels in an effort to
bring the PSU temperature down. If a problem still exists, a
sensing circuit will mute the power output channel that has the
highest temperature reading, thereby reducing the overall
temperature of the power supply until it reduces to a safe
operating level.
Always make sure that the dust filters behind the detachable front panel are clean to ensure maximum
possible airflow.

5.5 Operating Voltage

The label adjacent to the mains (AC) input connector indicates the AC mains voltage for which the
amplifier is wired and approved. The amplifier is built in two versions: 115 V and 230 V. Connect the
mains cable (AC cord) only to an AC source of the voltage shown on the label.
Any damage resulting from a PLM Series product
being connected to an AC source of incorrect
voltage will not be covered by the warranty.
PLM Series Operation Manual rev 1.1.3
5. Installation
15