Fixed or Removable Hot Swap Fans
Fans can certainly be the make or break to product sustainability in rackmount products. There are many strategies to cooling a unit. Fans and blowers are common. Conduction another. Managing airflow and direction is certainly strategic. Reliability is critical. In mission critical applications we frequently see redundant hot swap power supplies to maintain a powered up state. To the contrary, fan failures require a shutdown to take the unit out of service – for either repair or replacement.
Removable Hot Swap Fans
No matter if it’s a 1U or greater rackmount chassis, we have multiple hot swap fan (or blower) solutions to choose from. With nothing more than a screwdriver (for safety compliance) a fan module can be replaced as quickly as a hot swap power supply.
Fan Selection and Implementation
Fan selection typically includes considering size and availability, voltage, watts, CFM, static pressure and noise. Our fan solutions can encompass any axial fan you choose.
Our hot swap fan solutions dock with your board in the same manner for all sizes and configurations.
In more recent years we’ve seen more manufacturers implement dual rotor fans giving you more options.
Single vs. Dual Rotor Fans
When there is a bank of single rotor fans, common to many rackmount chassis, and a fan fails the airflow direction reverses. If all fans were exhausting, then one position is now an intake. This reduces overall chassis cooling by more than the loss of one fan. There is a lower percentage of airflow through the entire chassis. The failed fan circulates air to the fans adjacent and not through the chassis – reducing the performance of every fan in the system. The percentage of through chassis loss is based upon the pressure characteristic unique to the chassis assembly. If you are considering an N+1 approach, it’s not a true N+1 when a fan fails.
Enter Dual Rotor Fans. In a dual rotor fan there are two independently powered and monitor (if you select that feature) rotors within a single fan assembly. When one rotor fails the other rotor continues to spin. Thus airflow continues. There is generally some loss of overall airflow through the fan with the single failed rotor. The remaining dual rotor fans continue to perform vertically as before.
Fan Brackets – Grill vs. Guard
The fan brackets have two primary differences: perforated grill or wire grill. Each have Pros and Cons. So here they are:
Perforated Fan Grills
- Improved EMI containment for higher clock speeds.
- Increased noise from turbulence through the grill.
- Reduced airflow from reduced open area and grill proximity to the fan blades causing an increase in static pressure.
- More frequent service for dust removal.
Wire Fan Guards
- EMI containment for lower clock speeds.
- Lowest noise with greater distance to fan blades.
- Best airflow performance from least air restriction and effect on static pressure.
- Collects less dust for less frequent service.
Every fan option, irrespective of size, single or dual rotor, 2, 3 or 4 wire fan can be produced in either perforations or assembled with a finger guard. There is little cost difference between the two options.