NRG #40C Anemometer, Calibrated, With Boot

Model Number : 1900

The NRG #40C anemometer is the industry standard anemometer used worldwide. NRG #40C anemometers have recorded wind speeds of 96 m/s (214 mph). Their low moment of inertia and unique bearings permit very rapid response to gusts and lulls. Because of their output linearity, these sensors are ideal for use with various data retrieval systems.

A four-pole magnet induces a sine wave voltage into a coil producing an output signal with frequency proportional to wind speed. The #40C is constructed of rugged Lexan cups molded in one piece for repeatable performance. A rubber terminal boot is included.

A calibration certificate verifying that the sensor is traceable to the National Institute of Standards and Technology (USA) is available through electronic download.

Sensor type 3-cup anemometer
  • wind resource assessment
  • meteorological studies
  • environmental monitoring
Sensor range 1 m/s to 96 m/s (2.2 mph to 215 mph) (highest recorded)
Instrument compatibility all NRG loggers
Output signal
Signal type low level AC sine wave, frequency linearly proportional to wind speed
Anemometer Transfer Function
  • Consensus Transfer Function:
    Scale Factor (Slope): 0.765 m/s/Hz (1.711 mph/Hz)
    Offset: 0.35 m/s (0.78 mph)
  • refer to the white paper "The Maximum Type 40 Anemometer Calibration Project" for more information on the consensus transfer function
Output voltage at threshold 80 mV (peak-to-peak) minimum
Output voltage at 60Hz
  • 12 V (peak-to-peak) typical
  • output amplitude NOT proportional to wind speed
Calibration each anemometer individually calibrated, calibration reports provided via electronic download
Output signal range 0 Hz to 125 Hz (highest recorded)
Uncertainty Accuwind (Riso-R-1556) Classification:

  • Class 2.4A
  • Class 7.7B
    IEC 61400-12-1 operational standard uncertainty:
  • ± 0.14 m/s at 10 m/s for Class A
  • ± 0.45 m/s at 10 m/s for Class B
  • refer to calibration sheet for information on calibration uncertainty
  • refer to application note "#40C Anemometer Uncertainty" for definitions and more information
Response characteristics
Distance constant (63% recovery)
  • 2.55 m (8.37 feet) at 5m/s per ASTM D 5096-02
  • 2.56 m (8.40 feet) at 10m/s per ASTM D 5096-02
Moment of inertia
  • 1.01 x 10-4 kg-m2
  • 74.5 x 10-6 S-ft2
Swept diameter of rotor 190 mm (7.5 inches)
Mounting onto a 13 mm (0.5 inch) diameter mast with cotter pin and set screw
Tools required 0.25 inch nut driver, petroleum jelly, electrical tape
Operating temperature range -35 °C to 60 °C (-31 °F to 140 °F)
Operating humidity range 0 to 100% RH
Connections 4-40 brass hex nut/post terminals
Weight 0.14 kg (0.3 pounds)
  • 3 cups of conical cross-section, 51 mm (2 inches) dia.
  • 81 mm (3.2 inches) overall assembly height
Cups one piece injection-molded black polycarbonate
Body housing is black ABS plastic
Shaft beryllium copper, fully hardened
Bearing modified Teflon, self-lubricating
Magnet Indox 1, 25 mm (1 inch) diameter, 13 mm (0.5 inch) long, 4 poles
Coil single coil, bobbin wound, 4100 turns of #40 wire, shielded for ESD protection
Boot protective PVC sensor terminal boot included
Terminals brass

Have a question? Need help configuring and testing your NRG equipment? We're here to help. NRG Systems products come with five resources for technical support.

Product Documentation

Begin by reviewing the documentation we've prepared.

  • Read the manual: The answer to your question may be right there. Please help us to help you more effectively and read through your product's owner's manual first.
  • Application Notes or Reference Guide: Need more information about a specific product? Details about specific situations or settings can be found in the application notes.
  • Software Downloads: Just need to quickly check for a software update? This is the right place.
  • Check out the Knowledge Base: Find answers and solutions to common questions here. This is a constantly evolving database, so check it often for the latest and greatest information.

There's a good chance you're not the first person to have a specific question or issue. Check out our online Tech Forums where others like you go for answers. And if you feel you have something to offer, we welcome you to join in the discussion.

  • Search the Forums: Take a minute to search through our users forum. Often you'll find your question was answered before. If you don't find your answer, feel free to register and post your question.
  • Login to the Forums: Already a member of the forums? Welcome back!
  • Join the Forums: Ask questions, get answers and read suggestions from other customers on the NRG Tech Forums.

If you have checked the documentation, forums, and Knowledge Base and are still having problems with your equipment purchased within the past two years, you will need to contact NRG for a RMA return authorization number to return a defective product. This is the quickest and easiest way to get you back to doing what you are trying to do, measure the wind. Please see NRG Warranty for warranty details and instructions.

Repair Service

If you should need to return an out-of-warranty item for repair, please contact NRG in order to obtain an RMA number. Detailed instructions for returning an item to NRG can be found in the document Returning_Repairs_to_NRG.pdf.

Contact Technical Support

If you've explored all of the above resources and still have questions, we have a crack team of professionals waiting to answer your call or email. We ask that you be sure to use the tools above before contacting us, and we will do our best to assist you.