In the master's thesis, we address the development of an automated measurement station that
carries out the quality control of production of installation contactors and separates them based
on the noise they generate during operation. The device was designed according to the client's
requirements to provide a quality assessment based on five consecutive activation
measurements, as the noise level can vary from activation to activation. We also had to meet
the demands of the time cycle.
In the first part, we became acquainted with the principle of contactor operation and
investigated the source of noise. This was followed by a review of the theoretical background
of sound and vibration measurement. Using a single measured contactor, we tested the method
of noise measurement with a sound level meter and the measurement of vibrations using an
accelerometer and a contact microphone. The latter proved to be the most optimal method of
measurement. Due to the requirements of the time cycle and the number of necessary
measurements, we started designing a station for the simultaneous measurement of multiple
contactors. In doing so, we encountered a major problem of transmission of vibrations between
the measured contactors, which led to incorrect results. In the continuation, we solved the
problem by creating a clamping pallet that physically separates the measured contactors from
each other. For an even better effect, we also used vibration dampers. This adequately reduced
the mutual transmission of vibrations, but the problem still occurred with very buzzing
contactors. Furthermore, we introduced a method of selective measurement into the sequential
measurement of contactors, which separates highly deviating contactors from the rest and
measures them separately. With a detailed analysis of contactor measurements, we determined
an appropriate separation threshold that divides the contactors into quality and non-quality ones.
We concluded by fully automating the entire measurement process using a programmable logic
controller and creating a graphical interface for measurement management and monitoring.
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