Speed Sensors for Detecting Steel Targets

What Sensors are Needed for the Detection of Gears, Rack Gears, and Other Ferrous Targets?

For the detection of gears, rack gears, and other ferrous targets such as tone wheels, bolt heads, steel pins, rotating wheels, or discs there are two different magnetic sensing technologies to choose from.

• Hall Effect Gear Tooth Sensors with back biasing magnetic structures detect the changes in the internal magnetic field when the gear teeth or other ferrous targets pass by the sensor face and output a digital square wave pulse train. 
• Variable reluctance sensors use an internal coil, pole piece, and magnetic structure to generate a sine wave voltage output from passing gear teeth. 

To learn more about selecting or designing steel targets for Speed Sensors we offer an Application Note.

Speed Sensors for Detecting Magnetic Targets

What Type of Sensors are Needed for Detecting Moving Targets?

For detecting moving targets at greater distances, magnets can be attached to any object and then be detected using Hall Effect switches.  These sensors provide a digital output that turns on when a magnet is passing the sensor face.  Standard Hall Switches only detect the South Pole of the Magnet, but either pole Hall switches can be used in applications where the magnetic pole orientation is not known or cannot be guaranteed. 

The operate gap range is dependent on the sensor sensitivity and the size, shape, and material of the magnet.  We offer the following Application Note for comparing sensors and magnets in our catalog.

Target magnets of different sizes and materials are available with the South Pole Marked for use with our sensors.  We also offer magnets built into bolts and other threaded targets for easy installation and magnets built into clamping collars for mounting direct to rotating shafts.

If you do not find the speed detecting magnetic sensor or sensor target you need in our catalog, contact our Engineers to discuss a custom solution.