Computer Fans

Computer fans are used to cool computers and their associated components. They blow air into or out of computers and onto computer components in order to keep hardware at the correct operating temperature. Computer fans can be simple blowers, AC or DC fans that range from a few volts (V) to several hundred volts, or used with processors and power supplies. They can be large or small units, and either stand-alone devices or part of a heat sink. Typically, computer fans are very quiet and use DC brushless motors at either 5 or 12 VDC. Products with built-in temperature sensors can vary their speed accordingly. Common features for computer fans include lights and colors.

There are many different blower configurations for computer fans. Choices include axial, tube axial, vane axial, and multistage. Axial fans move air parallel to the axis of the fan and provide relatively high flow rates and low pressures. Tube axial fans feature a cylindrical housing with a propeller type fan. Vane axial fans feature a cylindrical housing with an outside diameter (OD) of blade tips that fit closely within the housing. This highly-efficient design provides a high-pressure capacity. Computer fans with multistage blowers produce very high static pressures at a low flow rate.

Centrifugal and crossflow blowers for computer fans are also available. Centrifugal or radial blowers move air perpendicular to the blower axis and provide relatively low flow rates and high pressures. Air enters around the center of the fan and exits around the outside. Crossflow or tangential blowers move air tangential to the axis of the fan and provide relatively high flow rates and low pressures. These computer fans are designed for applications that cannot fit a standard, high-airflow fan.

Computer fans carry both performance specifications and electrical specifications. Performance specifications include maximum air flow, maximum static pressure, and maximum sound level. Maximum air is rated typically in cubic feet per minute (CFM). Maximum static pressure is often measured in inches of water. Maximum sound level is usually measured at 3-ft. Electrical specifications for computer fans include motor voltage, operating current, and nominal power. With nominal power listings, horsepower (hp) is equal to 746 watts (W).

Motor type is an important parameter to specify when selecting computer fans. There are four main choices: 50/60 Hz AC, 400 Hz AC, DC, and brushless DC. Motors that operate at 0 to 60 Hz AC include single, multiphase, universal, servo, induction, and gear motors. Computer fans and other components that operate at 400 Hz AC are primarily used in aerospace applications. DC motors are commonly used in variable speed and torque applications. Brushless DC motors use internal non-contact sensing devices to activate external commutating electronics. They have armature windings on the stator and the field on the rotor.

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Part Numbers for Computer Fans