Comprehensive Analysis of Anemometers: Working Principle, Usage, Common Faults, and Repair Guide

I. Working Principle of Anemometers

Anemometers operate primarily based on the hot-wire effect. The core component is a fine metal wire (typically made of high-melting, ductile metals such as platinum, rhodium, or tungsten) placed in a fluid and heated by an electric current to a temperature higher than the surrounding fluid. When fluid (e.g., air) flows vertically past the wire, it carries away some heat, causing the wire’s temperature to drop. According to the theory of forced convective heat transfer, there is a direct relationship between the heat lost by the wire and the fluid’s velocity. By measuring the heat loss, the fluid’s velocity can be inferred.

II. Usage of Anemometers

Preparation Stage:

1. Check if the anemometer’s pointer is at zero; if not, gently adjust the mechanical screw to zero.
2. Insert the measuring rod plug into the socket, position the rod vertically, and tighten the screw cap to ensure the probe is sealed.
3. Set the “calibration switch” to the full-scale position and adjust the “full-scale adjustment” knob so that the pointer indicates full scale.

Measurement Process:

1. Set the “calibration switch” to “zero,” then adjust the “coarse” and “fine” knobs to return the pointer to zero.
2. Gently pull the screw cap to expose the probe and ensure the red dot on it faces the wind direction.
3. Based on the meter reading, consult the calibration curve to obtain the measured wind speed.
4. After measuring for a while (about 10 minutes), repeat the steps to standardize the current within the instrument.

Data Recording and Viewing:

1. To record data, press the record button, and the anemometer will automatically save the measurements.
2. Press the playback button to view previously measured data.

III. Common Faults and Repair Methods for Anemometers

No Output:

1. Power Issues: Check if the power cord is securely connected and measure the voltage stability.
2. Sensor Damage: Inspect the sensing element or circuit board for damage and replace the sensor if necessary.
3. Signal Transmission Problems: Check the signal wire connection, measure its integrity, and eliminate interference sources.

Abnormal Wind Speed Indication:

1. Reduced Sensor Sensitivity: Recalibrate the sensor or replace it with a new one.
2. Improper Installation: Ensure the sensor is installed in an unobstructed, vibration-free, and non-corrosive gas environment.

Stiff or Jammed Rotation:

1. Mechanical Faults: Check the sensor’s rotating parts for debris or wear, clean or replace components as needed.
2. Damaged Bearings: Replace damaged bearings to ensure smooth rotation.

Signal Interference:

1. Electromagnetic Interference: Check if the signal wire is shielded and keep it away from electromagnetic interference sources.
2. Radio Frequency Interference: Use sensors with stronger anti-interference capabilities or adjust the signal transmission method.

IV. Precautions for Using Anemometers

1. Ensure the anemometer is correctly calibrated before use and recalibrate periodically.
2. Avoid using the anemometer in combustible gas environments to prevent fires or explosions.
3. Do not expose the anemometer’s probe and body to rain to prevent electric shock or fire.
4. Clean the anemometer’s surface with soft fabric and neutral detergent; avoid using volatile liquids.
5. Store the anemometer in a dry, ventilated, dust-free environment, away from high temperatures, humidity, and direct sunlight.
6. Avoid subjecting the anemometer to strong impacts or vibrations to prevent damaging internal components.

V. Brands and Models of Anemometers Repaired by Longi Electromechanical

1. Testo
   • Testo 410 Series: 410-1 (Vane Anemometer), 410-2 (Vane Anemometer with Humidity Measurement)
   • Testo 425 (Hot-Wire Anemometer)
   • Testo 440 (Multifunction Anemometer)
   • Testo 480 (Professional Environmental Tester for Multiple Sensors)
2. Kestrel
   • Kestrel 5000 Series: 5100 (Wind Speed and Air Flow Meter), 5200 (Professional Weather Station with Environmental Measurement)
   • Kestrel 1000 (Portable Anemometer)
   • Kestrel 2000 (Anemometer with Temperature Measurement)
3. Extech
   • AN300 (Vane Anemometer)
   • AN400 (Hot-Wire Anemometer)
   • AN500 (Air Velocity and Flow Meter)
   • HD300 (Hot-Wire Anemometer with Data Logging)
4. Davis Instruments
   • Vantage Pro2 (Wireless Weather Station with Wind Speed Measurement)
   • Vantage Vue (Wireless Weather Station with Portable Design)
   • Anemometer (Professional Wind Speed Sensor)
5. Kanomax
   • 6006 (Hot-Wire Anemometer)
   • 6803 (Multifunction Anemometer with Data Logging)
   • 6810 (Vane Anemometer)
6. TSI
   • 9535 (Hot-Wire Anemometer with Data Logging)
   • 9545 (Hot-Wire Anemometer with Temperature and Humidity Measurement)
   • 5725 (Portable Anemometer)
7. Omega
   • HHF-SD1 (Hot-Wire Anemometer with Data Logging)
   • FMA-905 (Hot-Wire Anemometer with Temperature Measurement)
   • HHF81 (Portable Anemometer)
8. Fluke
   • 922 (Low-Velocity Anemometer)
   • 925 (Hot-Wire Anemometer)
   • 971 (Temperature and Humidity Meter with Wind Speed Measurement)
9. Alnor
   • EBT731 (Air Velocity and Flow Meter with Data Logging)
   • RVA801 (Portable Anemometer)
   • EBT720 (Professional Anemometer with Temperature and Humidity Measurement)
10. Amprobe
    • TMA-21HW (Hot-Wire Anemometer with Temperature and Humidity Measurement)
    • TMA-5 (Portable Anemometer)
    • TMA-40A (Air Velocity and Flow Meter)
11. CEM Instruments
    • DT-8894 (Vane Anemometer with Data Logging)
    • DT-618 (Hot-Wire Anemometer with Temperature and Humidity Measurement)
    • DT-318 (Portable Anemometer)
12. La Crosse Technology
    • EA-3010U (Air Velocity and Flow Meter)
    • TX60U-IT (Wireless Anemometer)
    • WS-2310 (Wireless Weather Station with Wind Speed Measurement)
13. PCE Instruments
    • PCE-TA 30 (Hot-Wire Anemometer)
    • PCE-009 (Portable Anemometer with Temperature Measurement)
    • PCE-AM 85 (Portable Anemometer with Humidity Measurement)
14. Lutron
    • AM-4204 (Vane Anemometer)
    • AM-4210 (Hot-Wire Anemometer)
    • AM-4220 (Portable Anemometer)

Longi Electromechanical Company has nearly 30 years of experience in repairing anemometers and can quickly repair various instruments. Additionally, they recycle and sell used anemometers. For inquiries, please contact us.