Which maintenance technology is most effective for detecting winding hot spots before insulation damage occurs?

• A. Thermography infrared imaging.
• B. Vibration analysis.
• C. Oil sampling only.
• D. Visual inspection only.

Answer: (A)

Detecting winding hot spots early relies on directly identifying abnormal heat patterns across the winding. Thermography infrared imaging does this by measuring surface temperatures over a wide area and creating a thermal map. Hot spots show up as distinct high-temperature areas, signaling cooling problems, poor connections, or winding faults before insulation damage occurs. Its non-contact nature allows rapid, full-field scanning of energized equipment, making it effective for locating localized heating that might be missed by other methods. Vibration analysis targets mechanical faults and may indicate misalignment or bearing wear rather than electrical heating in windings. Oil sampling reveals insulation degradation through oil condition and dissolved gas analysis but does not localize or detect heat buildup in windings. Visual inspection can only see visible signs and cannot reveal early thermal problems. So infrared thermography best identifies winding hot spots before insulation is compromised.