How to Test an Inducer Motor Hall Sensor

Inducer motors are used to drive blowers that deliver air in ventilation systems.

Inducer motors are used for heating and cooling the home, and they are found in exhaust systems in the kitchen. An inducer motor often features a Hall sensor. The magnetic field induced in a Hall sensor is used to detect the position of a motor shaft. As the sensor ages from exposure to moisture and other contaminants, the Hall sensor loses its effectiveness. Testing the sensor will help determine whether it's time to replace the inducer motor's Hall sensor.

Things You'll Need

• Inducer motor Hall sensor
• Documentation specific to inducer motor
• Digital multimeter with the appropriate leads

Instructions

1. Find the location of the Hall sensor for your specific model of inducer motor and disconnect the connector for the sensor. This connector should have three pins.

2. Review the pin connections and specifications for the Hall sensor. Research the documentation for your inducer motor to learn about each pin's designation. Also, find out what the measured voltages from the Hall sensor should be.

3. Prepare the digital multimeter for the test. According to the directions supplied with your specific digital multimeter, turn it on and make sure the leads are properly inserted. Based upon the desired output voltage from the Hall sensor, select the corresponding range in volts DC.

4. Connect the digital multimeter to the Hall sensor. Using the appropriate test leads, connect the negative lead to the ground pin of the Hall sensor connector. Connect the positive lead to the output voltage pin.

5. Obtain the output voltage reading. When the inducer motor switches on, check for an output reading in volts DC. Compare this reading against the nominal range of acceptable values.

6. Check the other output pin. Remove the positive test lead from the previous test reading. Reconnect this lead to the other voltage pin. Just as with the previous test, obtain the voltage reading for this connection.

7. Compare the measured results against the specifications of the nominal values. If the Hall sensor meets the specifications, then there should be no need to replace it. Otherwise, it will likely need to be replaced.

Tips & Warnings

• Probe style connectors that will fit into the pin connections are usually best to test Hall sensors.

• Keep your hands free from moving parts.

• Always exercise caution around live electrical components and take every precaution to avoid electric shock.

References

• Magnet Lab: Hall Effect
• Denver University: The Hall Effect and Hall Effect Sensors