Lab.gruppen PLM 20K44 Operation Manual

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Lab.gruppen PLM 20K44 Operation Manual Manual pdf 10 page image

3. Installation10PLM+ SERIES Operation Manual rev 1.0.03.3. Cooling3.3.1. OverviewThe PLM+ Series devices use a forced-air cooling system with airflow from front to rear, allowing high continuouspower levels without thermal problems. Front-to-rear airflow is preferable as air at the front of a rack is cooler thanthat at the rear in nearly all situations; never attempt to reverse the airflow. The operation of the PLM+’s coolingsystem is dependent on front-to-rear airflow; it will not function effectively with external airflow in the oppositedirection.Make sure an adequate air supply is provided in front of the PLM+, and that the rear of the PLM+ has sufficientspace to allow air to escape. If the PLM+ is rack-mounted, never operate the unit with any front or rear rack doorsor covers in position. It is recommended to keep the ambient temperature around the PLM+ as cool as possible.An increased temperature can have a significant negative impact on the expected lifetime on the componentsinside the PLM+.Note: Fit solid blanks (not ventilation blanks) to unused rack spaces to ensure effective air circulation.Leaving gaps in between items of equipment degrades the effectiveness of forced-air cooling.If installing one or more PLM+ Series devices in a rack with other fan-cooled equipment, be sure that all theother equipment also uses front-to-rear airflow for cooling. If this precaution is not observed, there is a risk ofoverheating, as units with the reverse airflow will be drawing in air which has already been heated by the PLM+s.3.3.2. Temperature Sensing and ProtectionThe PLM+ is equipped with a sophisticated temperature sensing system which protects it from any overheatingwhich may occur as a result of inadequate ventilation.Note: Always ensure the dust filters behind the detachable front panel are clean to ensure maximumpossible airflow.3.4. Operating VoltageThe label adjacent to the mains (AC) input connector indicates the AC mains voltage for which the device is wiredand approved. Both PLM+ models incorporate a universal power supply operating from 80 to 265 V. Only connectthe mains cable (AC cord) to an AC source of the voltage shown on the label.The PLM+ uses primary switching, which means the mains power is rectified on the primary side of thetransformer. This makes the power supply insensitive to mains frequency variation, and it will operate normally online frequencies from 45 to 75 Hz.