Key Process Control Points:
Winding Process: The strip material must be flat and tight, free from waviness, overlaps, or gaps. Tension must be constant and uniform to prevent internal stress imbalance.
Annealing Process (Core): Strictly monitor the annealing curve (heating, holding, cooling) and atmosphere to eliminate stress and restore magnetic properties. This is the critical step determining performance.
Forming and Curing: Impregnation (if required) or coating treatment must be uniform, with sufficient curing to ensure the core becomes a solid integral unit.
Finished Product Final Inspection:
Dimensional Accuracy: Check key dimensions such as inner/outer diameter, window height, and window width to ensure they conform to the drawing tolerances.
Visual Inspection: Must be free from rust, contamination, and physical damage (e.g., nicks, cracks).
Interlayer Insulation Test: Select points on the core's outer surface, apply a low-voltage DC current to measure resistance. The resistance value should be sufficiently high, indicating no interlayer shorts.
Ground Insulation Test: Use a megohmmeter to measure the insulation resistance between the core and the clamps. It is typically required to be > 500 MΩ.
Excitation Characteristic Test (Performance Verification): Wind a temporary coil around the core, apply a voltage corresponding to the rated magnetic flux density, and measure the no-load current and loss. The measured value should not exceed the design value by more than +15%.
