An Intelligent Automatic Transformer Turns Ratio (TTR) Tester is a sophisticated electronic instrument used to measure the ratio of turns between the primary and secondary windings of a transformer. The "Intelligent" and "Automatic" parts mean it can perform these tests quickly, accurately, and with minimal user intervention, often interpreting the results against predefined standards.
How It Works (Simplified Process)
Connection: The tester's leads are connected to the transformer's primary and secondary bushings.
Initiation: The user selects the test (e.g., single-phase, three-phase, with taps) and presses start.
Application: The tester applies a low-voltage, low-frequency AC signal to one winding (the HV side is common).
Measurement: It precisely measures the induced voltage on the other winding(s).
Calculation: Its internal microprocessor calculates the ratio (V_applied / V_induced).
Analysis: It compares the calculated ratio to the programmed nameplate ratio.
Output: It displays the result, the percent error, the excitation current, and a PASS/FAIL verdict.
Key Features of an Intelligent Automatic TTR Tester:
1. Automatic Ratio Measurement: Tests all phases and tap positions sequentially.
2. Excitation Current Measurement: A crucial diagnostic that helps identify shorted turns even when the ratio change is too small to detect.
3. Polarity Determination: Confirms the winding configuration.
4. Phase Angle Measurement (Vector Correlation): Advanced testers can measure the phase displacement between voltages, checking vector group (e.g., Dyn11, Ynd1).
5. Programmable Nameplate Library: Store hundreds of transformer specifications for quick recall.
6. Large Display & Data Management: Clear graphical LCD to show results and internal storage for data.
7. Built-in Printer/Data Export: For immediate hard copies or digital reports.
8. Safety Protections: Discharge circuits, warnings for live voltage, and robust enclosures.
An Intelligent Automatic Transformer Turns Ratio Tester is a modern, computer-based instrument that has revolutionized a critical power transformer test. It replaces slow, error-prone manual methods with a fast, accurate, and diagnostic-rich process that improves reliability, enhances safety, and simplifies the work of test technicians and engineers.
