The Crucial Role of Iron Cores in Transformer Design and Function

The transformer iron core serves a crucial role in the magnetic circuit of transformers, acting as its structural framework. Its design and manufacturing significantly influence various aspects of transformer performance, including losses, noise levels, insulation strength, and susceptibility to short circuits.

Manufacturing Process and Core Clamp Requirements

During the manufacturing process, strict compliance with detailed drawings, established standards, and operational procedures is critical. Live components must be securely interconnected, and all grounding points must provide reliable, high-quality contact to ensure safe and consistent performance.

Core Clamp Requirements

- Sufficient Strength: Core clamps must be robust enough to withstand mechanical stresses during operation.

- Welding Wire Strength: Welding materials should meet or exceed required strength specifications to ensure long-term structural integrity.

- Processing Accuracy: High precision is essential in manufacturing to maintain dimensional accuracy and fit.

- Defect-Free Welds: Welding points must be free of voids, gaps, or "bagging" to ensure proper load-bearing and electrical performance.

- Vertical Limb Alignment: Core limbs must be precisely aligned perpendicular to the base for structural stability.

- Vertical Centerline: The centerline of the pressure pin nut should remain perpendicular to the core limbs after welding, ensuring uniform compression.

- Planarity of Limbs: Both high- and low-voltage limbs—particularly at positions A and C—must lie on the same horizontal plane to maintain mechanical balance.

- Single-Pass Nut Engagement: Nuts must be threaded using a three-cone single-pass method to ensure secure engagement.

- Unpainted Contact Surfaces: Electrical contact areas should remain unpainted to ensure optimal conductivity.

- Chamfered Clamps: Clamp edges should be chamfered to eliminate sharp corners, reducing the risk of damage or stress concentration.

Key Points of the Core Stacking Process

- Preparation: Gather all necessary tools and materials, including clamps, insulation, sleepers, beams, pull plates, pressure pins, and foot insulation.

- Stack Placement: Position the core on a hydraulic lifting platform, ensuring it is aligned with the center of the platform.

- Platform Leveling: Confirm that the platform is level to maintain accurate core center alignment throughout assembly.

- Jack Placement: Position jacks with sufficient clearance to accommodate pull straps and clamps.

- Fixing Jacks: Secure the jacks firmly to the platform to ensure stability during stacking.

- Insulation and Alignment: Align insulation materials and clamps horizontally to ensure uniform assembly.

- Layer Stacking: Stack each layer sequentially, measuring dimensions precisely to maintain consistency.

- Nailing Frequency: Nail components at 5mm intervals to ensure structural integrity and prevent shifting.

- Tolerance Management: Adjust and compensate for dimensional tolerances between layers to ensure proper fit.

- Oil Channel Installation: Install oil channels strictly according to design specifications for efficient cooling.

- Support Plate Placement: Accurately position support plates to provide structural reinforcement.

- Verticality Check: Perform vertical alignment checks at each stacking stage to maintain accuracy.

- Final Assembly: Install crossbeams, tie straps, and equal-thickness pads to prevent deformation and reduce operational losses.

- Cleaning Debris: Thoroughly clean the assembly area to remove any debris or foreign objects.

- Tensioning Straps: Apply and secure tensioning straps to firmly bind the core to the platform.

- Insulation Resistance Check: Conduct an insulation resistance test after assembly to verify electrical integrity.

Grounding and Safety

The transformer core must be grounded at a single designated point to ensure electrical safety and prevent circulating currents.

All metal components connected to the core should be maintained at zero potential to eliminate the risk of electric shock or unintended current flow.

Dual-point grounding must be strictly avoided, as it can create closed loops, leading to circulating currents, overheating, or potential equipment damage.

Strict adherence to grounding protocols and safety standards ensures that the transformer operates reliably and safely, meeting both regulatory and operational requirements.