Products Catalog

Specification

Deformation of a brake disc under stress

To obtain accurate data on the de-formation of brake disc friction rings under stress, they must be measured under extreme conditions. Nominal speed: 2000 1/ min. Surface temperature: approx. 600 ° C The following demands are therefore made on the measuring system:
1. High bandwidth for frequency analyses up to the
10th harmonic.
2. High accuracy minimum zero shift with change
in temperature, no change in measuring signal
due to temperature-related changes in magnetic
and conductive properties.
3. High resolution because deformation takes
place in the range < 100 ì m.
This measurement can be reliably made using the
non-contact capacitive displacement measuring system capaNCDT.

The capacitive measuring principle
The carrier frequency ( 20 kHz) supplied by a constant current source generates a voltage drop
over the sensor which is proportional to the distance between the sensor surface and the friction ring . This voltage change is fed through preamplifier/ demodulator electronics which supply
an analog signal at the output of the measuring amplifier. Very good linearity of the output signal is achieved by the gurad ring capacitor principle.