OMICRON Webinar: 

How Vibro-Acoustic Measurement (VAM) method along with Dynamic Resistance Measurement  (DRM) provides comprehensive OLTC diagnostics

April 20, 2022

*Qualified for 1 PDU by Professional Engineers Board (PEB) of Singapore


On-load tap changers (OLTC) play a vital role in regulating the voltage level in the electrical grid. Depending on the load, the transformer turns ratio has to be adapted during operation by the OLTC. These mechanical switching operations can lead to wear and tear of the tap changer contacts over time. Vibro-Acoustic Measurement is the new approach implemented in TESTRANO 600 to assess the condition of OLTC under online and/or offline conditions. Utilizing both Dynamic Resistance Measurement (DRM) and Vibro-Acoustic Measurement (VAM) helps in performing an overall in-depth OLTC diagnostics where DRM helps in analyzing the changes in electrical characteristics while VAM focuses on the unique mechanical vibration patterns during the switching process.

Date: April 20, 2022 (Wednesday)
Time: 02:00 pm – 04:00 pm, Hong Kong Time (GMT +8)


An Overview of OLTC dynamic resistance measurement (40 mins)
  • OLTC condition verification using
    • Static winding resistance measurement
    • Dynamic resistance measurement
    • 3-phase dynamic resistance measurement
Vibro-acoustic measurement (VAM) as a complementary OLTC diagnostic tool (50 mins)
  • Theory of VAM
  • Enhanced OLTC diagnostics combining DRM & VAM

Demonstration shall follow to facilitate your understanding of the measurement methods





Medium of instruction


Registration fee
Free of charge


Mode of delivery
This session will be delivered online by Cisco Webex Software. Upon successful registration, you will receive the meeting information by email and will be able to join this online session with your desktop computer, tablet or mobile phone.

Please feel free to email for enquiries.

*The event program is subject to change without prior notice.