4-Wire Pulse Width Modulation (PWM) Controlled Fans Specification

Environmental and Reliability
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5 Environmental and Reliability
5.1.1 Operating Temperature
Fan shall be capable of sustaining normal operation over an ambient inlet temperature range of
0°C to 70 °C.
5.1.2 Non-operating Humidity
Fan shall be capable of sustaining normal operation at +55 °C / 85 %R.H.
5.1.3 Non-operating Thermal Cycling
Fan shall be capable of sustaining normal operation after being subjected to -5 °C to +70 °C for
1000 cycles; ramp = 20 °C/min; 10 min dwell.
5.1.4 Power Cycling
Fan shall be capable of sustaining normal operation after being subjected to 7,500 on/off cycles,
each cycle specified as 3 minutes on, 2 minutes off at 70°C ambient temperature. The sample size
is 12 units for this test.
5.1.5 Reliability
Mechanical wear out represents the highest risk reliability parameter for fans. The capability of
the functional mechanical elements (ball / sleeve bearing, shaft, and tower assembly) must be
demonstrated to a minimum useful lifetime of 50,000 hours.
The fan must pass the reliability test criteria with the fan operating at rated voltage in a high
temperature environment. Readouts include RPM, Icc and Noise. No infant mortality defects
allowed.
Note: These are minimum requirements. The end customer should review vendor collateral and have
their specific requirements reflected in a purchasing specification.
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