Brake rotor thickness is a critical measurement for automotive safety. Not only the overall thickness, but variations in thickness at different locations around the rotor. Hard braking and inadequate cooling can cause brake rotors to wear unevenly.
During the design phase, brake rotors are tested under different braking conditions. Without the noncontact capacitive sensors, the rotors would have to be removed and then measured for variations in thickness and reinstalled for further testing.
Using capacitive sensors, the rotor thickness can be monitored without the need for disassembly. The sensors have a wide bandwidth of 15kHz making them able to read the thickness at many discrete points around the rotor.
For more detail on thickness measurement with capacitive sensors, see our Thickness Application Note.