Types and Selection of Transformer Laminated Wood

Time: 03-06 2026 Auther: Xujue Electrical

Electrical Laminated Wood is a high-performance insulating material made from high-quality wood veneers (typicall...

Electrical Laminated Wood is a high-performance insulating material made from high-quality wood veneers (typically beech or birch) impregnated with synthetic resin and cured under high temperature and pressure. It is widely used in oil-immersed transformers for pressure plates, supporting parts, oil-gap spacers, and lead wire brackets.

1. Common Types and Comparison

Laminated wood is primarily classified by wood species and density (compression ratio):

Classification	Common Types	Characteristics & Recommendations
By Wood Species	Beech Laminated Wood	Highest strength and dense texture. Best for load-bearing components in large-capacity or UHV transformers (e.g., coil pressure rings).
	Birch Laminated Wood	Good toughness and better machinability. Costs slightly less than beech; used for general insulation supports in small-to-medium transformers.
By Density	Normal Density (0.75-0.95g/cm³)	Lighter and easy to machine. Suitable for lead wire brackets or secondary supporting parts.
	High Density (1.0-1.35g/cm³)	Extremely high mechanical strength. Used for coil pressure blocks that must withstand high axial pressure.
By Resin Type	Phenolic Based	Low cost, temperature resistant up to105℃ (Class A). The standard choice for distribution transformers.
	Epoxy Based	Better dielectric properties, temperature resistance up to 130℃ . Used for high-performance or high-voltage equipment.

2. Selection Guide

When selecting laminated wood, consider the operating environment and structural stress:
Stress Load Matching:
High-Voltage Coil Blocks: Prioritize high-density red beech. Its superior compressive strength prevents coil displacement during short-circuit current impacts.
General Brackets: Choose birch or medium-density wood to balance structural strength and weight reduction.
Insulation Environment Matching:
Oil-Immersed Transformers: The dielectric constant of laminated wood is close to that of transformer oil (approx. 2.0-3.0). Ensure extremely low moisture content to prevent bubble formation during long-term operation.
High-Heat Environments: If continuous operating temperatures exceed, switch to epoxy-based materials meeting Class F insulation requirements.
Machining Precision:
For precision parts (like threaded fasteners), select high-density wood. It offers better screw-holding power and shear resistance, preventing edge chipping or delamination during machining.

3. Alternative Materials

Comparison with G10/FR4: G10 has higher mechanical strength and nearly zero water absorption but is significantly more expensive. In extra-large capacity transformers, G10 may replace laminated wood at core stress points, but laminated wood remains the preferred choice for general components due to cost-efficiency and insulation compatibility.

4.Manufacturer selection

XUJUE ELECTRICAL has over 65 years of experience in producing transformer Laminated Wood insulation materials, ensuring reliable quality and stable performance. Throughout customer service, Xujue’s professional team can provide suitable specifications and models of transformer Laminated Wood based on the specific requirements and application scenarios of transformer manufacturing. Whether for small batches or large-scale production, Xujue responds promptly, offering attentive service and high-quality products.

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