Transformer Turns Ratio (TTR) Testing:
What it is: A critical test performed on electrical transformers (power transformers, instrument transformers like CTs & VTs).
Definition: It verifies the ratio between the number of turns in the primary winding and the number of turns in the secondary winding. This ratio directly determines the voltage transformation (e.g., a 10:1 turns ratio steps 1000V down to 100V).
Purpose of Testing:
Manufacturing QA: Ensure the transformer is built to the correct design specifications.
Commissioning: Verify correct installation and wiring before energizing.
Diagnostics & Maintenance: Detect shorted turns (which change the ratio), open circuits, incorrect tap settings, or other winding issues. It's a fundamental test for transformer health assessment.
How it's done: A specialized Turns Ratio Tester applies a known low AC voltage to one winding and precisely measures the induced voltage on the other winding(s). The measured ratio is compared to the nameplate ratio or expected value.
