Electrical Laminated Wood for Transformers: Birch vs Beech Comparison Guide

Time: 10-30 2025 Auther: Xujue Electrical

Electrical Laminated Wood Birch vs Beech In oil-immersed transformers, electrical laminated wood is commonly made fr...

Electrical Laminated Wood Birch vs Beech

In oil-immersed transformers, electrical laminated wood is commonly made from birch or beech.Although both materials serve similar purposes, they differ in performance and application areas.
Here’s a detailed comparison：Beech laminated wood VS Birch laminated wood

Beech laminated wood

Birch laminated wood

I. Basic Concept

Electrical laminated wood is a composite insulation and structural material made by rotary-cutting birch or beech veneers, drying, gluing, and hot-pressing them with the grain directions alternately layered.
It is widely used in transformers, reactors, and motors for mechanical support and electrical insulation.

II. Comparison: Birch Laminated Wood vs. Beech Laminated Wood

Item	Birch Laminated Wood	Beech Laminated Wood
Wood Characteristics	Fine texture, light color, medium density	Coarser texture, darker color, higher density
Mechanical Strength	High strength and toughness, good impact resistance	Higher strength and hardness, better compression resistance
Density (g/cm³)	0.75–0.85	0.9–1.3
Moisture & Dimensional Stability	Better stability, less deformation	Slightly more hygroscopic, affected by humidity
Machinability	Easy to cut, drill, and machine with smooth finish	Harder to process, causes more tool wear
Oil Resistance	Excellent, suitable for long-term oil immersion	Superior, stable under high-temperature oil conditions
Electrical Insulation	Dielectric constant ≈ 4.2 (close to transformer oil)	Similar dielectric constant, higher dielectric strength
Weight	Lighter	Heavier
Cost	Relatively lower	Relatively higher
Typical Applications	Small and medium oil-immersed or dry-type transformers	Large or high-voltage transformers, load-bearing parts

III. Selection Recommendations

Application Scenario	Recommended Material	Reason
Standard oil-immersed transformers (≤110kV)	Birch laminated wood	Cost-effective, stable, easy to process
High-voltage or large-capacity transformers (≥110kV)	Beech laminated wood	High strength, heat- and oil-resistant, low deformation
Lightweight or high-insulation structures	Birch laminated wood	Lower density, excellent dielectric properties
High mechanical stress parts (press rings, clamping plates)	Beech laminated wood	Superior rigidity and compressive strength

IV. Summary

Birch laminated wood — lightweight, easy to machine, and cost-effective; ideal for general electrical equipment.
Beech laminated wood — stronger, more heat- and oil-resistant; best for large, high-voltage transformers and stressed components.

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