Most AC fans can operate on two frequencies: 50 or 60 Hz. This frequency is determined by the power source and affects the fans speed. A fan running on 60 Hz will spin faster than if it were running on a 50 Hz frequency. A faster spinning fan generates more airflow, static pressure, and noise. To account for these differences, a fans data sheet usually includes a set of specifications for each frequency. Note that the power from an electric outlet in North America has a 60Hz frequency.
|Fans create positive static pressure when moving air. The environment the fan operates in has a negative static pressure that resists air movement. In an enclosed space, the tightly packed air generates high amounts of negative static pressure which will reduce the fans airflow. A fans static pressure rating, measure by mm-H2O reflects how well it will operate under negative pressure. The higher the number, the better it will perform. Not all fans require a high static pressure rating; it depends on the application and operating environment.|
All fans have to consume power in order to operate. The power a fan consumes is measured in watts or W. The higher the watt rating, the more power it uses. Large and high-speed fans typically consume more power than smaller and lower speed fans.
Rotations Per Minute [RPM]
The RPM rating represents how fast a fan is spinning per minute. Holding all other specifications constant, a faster spinning fan will generate more airflow and noise. When designing a fan, many engineers will reduce a fans speed so that it delivers an acceptable airflow while minimizing the noise level.
AC Terminal Connectors
Terminal connectors are two metal prongs that stick out from a side of the fans enclosure. Terminals are more convenient than wire connectors by reducing the need for soldering. They are also more versatile by being able to be easily attached to various fan cords.
Wire Cord: A wire fan cord essentially converts a fan with terminals into wires connectors. One end of the cord can be attached to the fans terminals, and the other end can be soldered onto the power source. When the fan needs to be replaced, you can easily detach the fan from the cord and attach on a new fan. In contrast, using fans that originally had wire connectors would require soldering each time.
Power Plug Cord: A power plug fan cord allows a terminal connector fan to be plugged into an electric outlet. One end of the cord can be attached to the fans terminals, and the other end is a standard power plug. The power plug can then be plugged into any standard electric outlet. When the fan needs to be replaced, the power plug cord can be easily be detached to be used on the new fan.
AC Wire Connectors
|Wire connectors, also known as leads, are two wires sticking out of the fan. The wires are enclosed in black plastic to prevent contact. At the tip, the actual metallic portion is revealed to be connected to a power source. Wires can also be soldered onto power cords to be plugged into an electric outlet. In any case, soldering would be required each time the fan needs to be replaced.|
|DC fans usually have two or more wire connectors. The first wire on a DC fan is colored red and the second wire is colored black. This is because the red wire must receive a positive voltage and the black wire must receive a negative voltage. Many DC fans have a third or fourth wire of a different color such yellow or white. These additional wires help control special functions on the fan such as thermistor or PWM. Often, all the wires on the DC fan is bounded together with a molex or pin connector at the end.|