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| DC fan general specification : |
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1. |
Operation temperature: |
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-10 ℃ to + 70 ℃ . (humidity: 35%~85%RH) |
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2. |
Storage temperature: |
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-40 ℃ to + 75 ℃ . (humidity: 35%~85%RH) |
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3. |
Insulation resistance: |
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10mega OHM MIN. At 500VDC (between frame and (+) terminal) |
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4. |
Dielectric strength: |
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5mA MAX. at 500 VAC 60 Hz one minute (between frame and (+) terminal) |
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5. |
Vibration resistance test: |
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Applied 5.30Hz, 0.04 peak to peak amplitude, 30-500Hz, 2G peak amplitude for five minutes to all three axis. |
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Fan shall satisfy the specified performance standards. |
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6. |
Shock test: |
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Under the conditions of 60G , 11 ms (1/2 sine), two times to all three axis, it shall satisfy the specified performances standards. |
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7. |
Protection: |
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(1) Impedance protection: The rotor drive shall be restricted for 72 hours in the state where is made in the |
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range of operating temperature and operating voltage. In shall not fail. |
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(2) Locked current protection:DC fan has over current protection circuit with auto restart after after 3 seconds. |
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8. |
Life expected: |
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Mean endurance time until the revolution drops by 30% of the initial value in the condition of continuously running under |
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standard environmental condition and rated condition. |
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9. |
Polarity protection: |
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The fan will not cause damage when reverse rated voltage is connected. |
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Noise characteristics： |
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Noise measurements are central values as measured at a point 1m from the suction surface of a fan suspended |
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and at rated voltage in an anechoic room with LARSON DAVIS type 824s sound level meter. |
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Air flow and static pressure characteristics： |
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The performance including air flow and air pressure measured at rated voltage in double chamber is measured |
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according to AMCA 210-99 standard as shown below: |
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| Conversion table： |
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Static pressure： |
Air flow： |
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1 mm H 2 O= 0.0394 inch H 2 O |
1 m 3 /min= 35.31 ft 3 /min (CFM) |
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1 mm H 2 O= 9.8 Pa (Pascal) |
1 CFM= 0.0283 m 3 /min |
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1 inch H 2 O= 25.4mm H 2 O |
1 m 3 /min= 16.67 I/sec |
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1 inch H 2 O= 249 Pa |
1 CFM= 0.472 I/sec |
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1 I/sec= 0.06 m 3 /min |
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| Signal & control： Frequency generator (FG) signal |
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Pulse sensor produce two-cycle rectangular waves per rotation of fan motor. These are best suited for |
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detecting rotating speeds. Pulse sensors can be incorporated in all kinds of DC fans motors. |
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Output circuit : |
Specifications : |
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Output type: open collect |
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VFG maximum voltage |
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◎13.8V as 12V Voltage fans |
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◎26.4V as 24V Voltage fans |
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◎56.0V as 48V Voltage fans |
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Ic maximum current= 5mA |
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Output waveform : |
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During normal run |
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T= T1+T2+T3+T4= 60/N (Sec) |
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N: SPEED (RPM) |
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Rotation detector (RD) signal： |
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| PWM (pulse width modulation)： |
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In PWM speed control, a fixed frequency square wave is applied to the speed control of the fan. |
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The ratio of the on time vs. the PWM period is proportional to the RPM. |
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To control signal line of the fan, the frequency of PWM shall be able to accept a 30 HZ to 30kHz. |
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The preferred operating point for the fan is 0%~100% duty cycle. |
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Using Fan by Parnell and Series arrangement : |
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Estimate Fan Air flow and Pressure |
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For identical fans in parallel, P max = P max,single, Q max = Q max,single x no.of fans |
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| Fan Choice by Your System Impendence : |
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Every system has an impedance curve. System impedance is generally proportional to Q2. |
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Operating point is the intersection of P-Q curve and the impedance curve. The use of impedance |
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curves is to select a fan that provides maximum air flow rate at the operating point. |
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