Vibration tester VAM1

for transformers

Vibro-acoustic measurements for On Load Tap Changers Listen to what your OLTC has to say The vibro-acoustic measurement (VAM) method focuses on the mechanical integrity of the On Load Tap Changer. The OLTC is a mechanical switching device that regulates the system voltage by adjusting the transformer turns ratio. Due to the thermal and mechanical stresses generated when switching the load current, various OLTC components such as the contacts can suffer wear and tear over their lifetime. Therefore, the new VAM1 accessory for TESTRANO 600 records a detailed vibration pattern produced during the switching operation using piezoelectric sensors. These sensors are temporarily mounted to the power transformer tank via magnets. The results are compared with reference data such as a fingerprint or previously recorded data. Mechanical deviations in the OLTC will lead to an altered vibration pattern and thus be detectable. The VAM solution can be performed offline or while the power transformer is still connected to the grid.