On-load tap changer analyzer

Data records

• An on-load tap changer analyzer is a winding resistance test set extended to record what happens during a tap change: it keeps a direct current flowing through the winding while the tap changer operates and captures the current, the winding voltages and often the drive motor current against time. Source: Electrical Testing Reference editorial taxonomy, 2026-10 edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.definition
• Dynamic resistance measurement captures the transient current through the tap changer as it moves from one tap to the next, revealing contact wear, timing deviations and interruptions that a static resistance measurement taken at rest on each tap cannot show. Source: OMICRON application page, web page edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.dynamic-resistance-measurement
• The analyzer records the current drawn by the tap changer drive motor during the operation to identify problems in the drive system, and the motor current can be recorded with the transformer in service, when the measurement scope is limited to the motor current and vibration signals. Source: OMICRON product page, web page edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.motor-current
• A ripple test is a dynamic measurement in which the test current is recorded during the tap change and the dip in current, expressed as a fraction of the test current, indicates the transition behavior, but it cannot give transition resistor values or transition times. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.ripple-test
• A static measurement taken at rest on each tap position reveals loose joints, poor connections, thermal damage and an imbalance between phases; a dynamic measurement, which records current and voltage continuously through the transition, adds contact timing, the condition of the transition resistors, slow or sticking operation and intermittent or noisy transitions. Source: Megger application page, web page edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.static-versus-dynamic
• The results of a dynamic resistance measurement on a tap changer are evaluated by comparative analysis of three quantities: the transition timing, the ripple and the resistance values. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.timing-evaluation
• The instrument class is written On-load tap changer analyzer. Value: On-load tap changer analyzer. Source: Electrical Testing Reference editorial taxonomy, 2026-10 edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.title
• To obtain true transition resistances and times, one method measures the test current together with the voltages on both the high-voltage winding and the open low-voltage winding during the operation; the low-voltage winding voltage is purely inductive, so a transformer model separates the inductive part from the high-voltage winding voltage and leaves the resistive part from which the resistance is calculated. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.transition-resistance-method
• Vibro-acoustic measurement complements dynamic resistance measurement by recording the vibration signature of the tap changer during switching through sensors mounted on the tank, which can be done with the transformer in service; changes in the pattern against a reference indicate contact wear, mechanical misalignment or drive problems. Source: OMICRON product page, web page edition. Verified 2026-10-27. Record instr.on-load-tap-changer-analyzer.vibro-acoustic-measurement