Fan Comments
Chassis fans may be selected to operate off either AC or DC power. Fans powered from AC do not impose a load on the chassis power supply while a DC fan will draw from the internal power supply. The life expectancy of a DC fan is higher than that of a comparable AC fan, independent of the type of bearing system employed, since DC fans are up to five times as efficient.
Select an AC fan if the internal chassis power supply is limited in wattage, or the chassis temperature rise is restricted. AC fans draw their current from the AC line voltage so do not cause any power supply loading, resulting in a smaller power supply and less heat generated within the chassis
Select a DC fan to achieve Mean-Time-Between-Failures [MTBF] requirements. A DC fan has a longer life expectancy than an AC fan. As an example, a DC fan may have a life expectancy of 40,000 hours, while an AC fan may be slightly less [number in review]
Brushless DC fans are available at three nominal voltages: 12V, 24V and 48 Volts. The speed [RPM] and airflow [CFM] of a typical DC fan is proportional to the voltage supplied.
Fans, Fan Trays, Fan Accessories, Blower Manufacturers
Next topic Slot Bypass Cards, in this section.
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Both AC or DC fans are available in the same sizes compatible with chassis use and both use Cubic Feet per Meter [CFM] to describe air flow, and Revolution Per Minute [RPM] to describe fan speed.
How to Index; How To Specify a Equipment Chassis
