Language
Views: 99 Author: Site Editor Publish Time: 2026-08-12 Origin: Site
The core lamination principles for dry-type transformers and oil-immersed transformers are highly consistent, both pursuing low loss and high magnetic permeability. For example, both commonly use high-quality cold-rolled oriented silicon steel sheets and the 45° fully mitered joint technique. However, their specific process details differ significantly due to different cooling and insulation methods.
The following table compares the differences between the laminations of dry-type transformers and oil-immersed transformers across several key aspects:
Comparison | Dry-Type Transformer | Oil-Immersed Transformer | Key Points |
Cooling and Insulation Medium | Air cooling, solid insulation | Transformer oil cooling, oil-paper composite insulation | Fundamental difference that directly affects heat dissipation and insulation process design. |
Core Cross-Section and Shape | Cross-section can be circular, elliptical, or use a patented "D"-shaped yoke to save material. | Cross-section can be circular or elliptical, with some patents using elliptical designs to improve short-circuit withstand capability and material utilization. | Both are continuously optimizing cross-sectional shapes to reduce costs while ensuring performance. |
Lamination Process Characteristics | Often adopts stepped lamination and applies epoxy anti-rust paint immediately after lamination to reduce losses and noise. | Commonly adopts the non-stacked upper yoke process, i.e., stacking all parts except the upper yoke on the lamination table first, then clamping and binding, and finally installing the windings. | Core difference: Dry-type focuses on paint protection; oil-immersed uses "non-stacked upper yoke" to facilitate subsequent winding assembly. |
Core Fixing Method | Uses clamp plate and pressure pin structure, and binds the core limbs with epoxy tape to enhance structural strength. | Uses C-clamps and hydraulic jacks for temporary fixing of core limbs and yokes, then binds with glass fiber tape. | Fixing methods are designed to match their respective insulation and structural designs. |
Level of Automation | Widely adopts automated processes such as automatic stacking and automatic flipping, offering high precision and efficiency. | Large power transformers also use advanced core turning tables to ensure lamination precision and reduce no-load losses. | Both are moving toward high-precision automation. |
Reasons Behind These Differences
These process variations are primarily determined by their application scenarios:
· Dry-Type Transformers: Commonly used indoors, with extremely high requirements for safety and fire protection. Therefore, they contain no flammable oil and rely entirely on air cooling and solid insulation. Rust prevention and local temperature rise control on the core are more stringent. Air ducts are often designed into the core structure to assist heat dissipation.
· Oil-Immersed Transformers: Commonly used outdoors, featuring high heat dissipation efficiency and strong overload capacity. The "non-stacked upper yoke" process is adopted so that the windings can be assembled onto the core limbs first, with the upper yoke installed last to close the magnetic circuit. This design is well-suited for the manufacturing process of large transformers.
