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The Fairmount Potentiometric Windvane has the following features:
Operation
The precision wirewound potentiometer is mounted in an all-weather, corrosion resistant case. It has the lowest possible torque consistent with long life and reliable operation. The small gap at North is filled with an insulating material to ensure smooth operation over the full 360°. The vane arm is attached by a unique gravity fastener, giving rapid and reliable attachment & release in portable applications.
Performance
Maximum wind speed : over 75 m/s (150 Kts, 170 mph.).
Threshold : 0.6 m/s (1.2 Kt, 1.4 mph.) - tne fin will commence movement when aligned at 45° to the flow.
Response : Distance constant : 2.3 metres
: Damping ratio: 0.2
Range : 360° mechanical angle, full circle continous rotation allowed.
Backlash : +/- ½° fin removed <N replaced (no measureable backlash movement during use).
Life : 5 x 107 cycles (10 years of typical exposure).
Accuracy : + 2° obtainable in steady winds over 5m/s.
Temperature range : - 50 to + 70 °C (de-icing heater to order).
Electrical
Potentiometer resistance : 1000 Ohms + 10%
Maximum dissipation : 0.5W, -50 to +20°C (derate linearly to 0.25W at +70°C)
Wiper current : 20mA max.
Supply voltage : 20V max.
Case to pot voltage : 125V max.
Temperature coeff. : +50 ppm/°C
Electrical continuity angle : 357.7° +1.5° (2.3° gap at north)
Electrical variation angle : 356.5° +1.5° (3.5° deadband)
Resolution : +0.2°
Repeatability : +0.5°
Linearity : 0.5% of full range output.
Ordering Information:
FM 2004 Potentiometric Windvane
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