Power cooling module (PCM)

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AC-DC power is provided by up to four auto-ranging power cooling modules (PCMs) with integrated axial cooling fans, up to 2 in each module. The SBB I/O modules control the fan speed. See the section that describes the system airflow.

580W PCM

A 580W PCM voltage operating range is nominally 100V - 240V AC. Also see the System airflow section for optimal cooling within the enclosure(s).

Figure 1. 580W Power Cooling Module
580W PCM

Figure 2. 580W PCM LEDs
580W PCM
Table 1. LEDs - 580W PCM
PCM LED LED behavior status
PCM OK Green
AC Input Fail Amber
Fan Fail Amber
DC Output Fail Amber

Multiple PCMs

The IBM COS small disk enclosure system includes two PCMs in multiple PCMs that provide redundant power control for the system. This is done so that if one PCM fails, the other(s) maintains the power supply and enclosure operation is not affected while you replace the faulty module.

PCMs are hot-pluggable and replacement should only take a few seconds to do. Replacement must be completed within a few seconds after the removal of the defective PCM.

Note: Important Operation of the enclosure with ANY modules missing will disrupt the airflow and the drives will not receive sufficient cooling. It is ESSENTIAL that all apertures hold active or dummy drives before you switch on the enclosure system.

Multiple power supply unit modules

The storage system includes two PSUs which provide redundant power control for the system so that if one module fails, the other maintains the power supply, and enclosure operation is not affected while you replace the faulty module.

PSUs are hot-pluggable, and replacement should only take a few seconds to do. Replacement must be completed as soon as possible after the removal of the defective PSU to avoid a thermal exception. The replacement procedure should be completed within an absolute maximum of three minutes.

Important:

Operation of the enclosure with any modules missing will disrupt the airflow, and the disks will not receive sufficient cooling. It is essential that all slots are fitted with PSUs prior to powering on the enclosure.

System airflow

The system must be operated with low pressure rear exhaust installation. Back pressure created by rack doors and obstacles is not to exceed 5 pascals (0.5mm water gauge). The cooling system provides sufficient capacity to ensure that maximum temperatures are not exceeded.