Transformer Turns Ratio (TTR) testing helps identify several critical issues in transformers, ensuring their proper operation and safety. Key issues that can be detected include:

1. Shorted Windings: TTR testing can reveal short circuits within transformer windings, where some turns of the coil have become shorted, leading to incorrect voltage ratios and poor transformer performance.

2. Open Circuits: The test can identify open windings, where the continuity of the coil is broken, affecting the transformer's ability to operate.

3. Incorrect Transformer Connections: If the windings are connected improperly, TTR testing will show an incorrect ratio, alerting to configuration problems during installation or after repairs.

4. Winding Damage: Physical damage to the windings, whether from mechanical stress, overheating, or external impacts, can result in a failed TTR test, indicating that the transformer needs repair.

5. Core Problems: Although primarily testing the winding ratio, significant core issues such as partial core saturation or physical misalignment can sometimes be detected, as they might affect the voltage ratio indirectly.

6. Manufacturing Defects: If a transformer has been assembled with incorrectly wound or improperly configured windings, TTR testing will reveal deviations from the expected ratio, which can point to manufacturing issues.

These issues are critical to identify to prevent transformer failure, equipment downtime, and potential safety hazards.