G10 vs FR4 vs UPGM: Best Insulation Materials for Wind Turbines

Time: 12-09 2025 Auther: Xujue Electrical

G10 / FR4 / UPGM Application Comparison Table Item G10 Epoxy Laminate FR4 Flame-Retardant Epoxy Laminate...

G10 / FR4 / UPGM Application Comparison Table

Item	G10 Epoxy Laminate	FR4 Flame-Retardant Epoxy Laminate	UPGM (Unsaturated Polyester Glass-Mat Laminate)
Base Material Structure	Glass cloth + epoxy resin	Glass cloth + flame-retardant epoxy resin	Glass fiber mat + unsaturated polyester resin
Flame Retardancy	Moderate (non-FR)	Excellent, UL94 V0	General (non-FR)
Thermal Class	Class F (155°C)	Class F–H (155–180°C)	Class B–F (130–155°C)
Mechanical Strength	High	High (slightly higher than G10)	Medium
Water Absorption	Low	Very low	Slightly higher
Dielectric Strength	High	Very high; suitable for high-voltage areas	Medium
Moisture / Salt Spray Resistance	Good	Excellent (ideal for offshore wind)	General
Cost	Medium	Slightly higher	Low
Machinability	Good	Good	Excellent (easy to machine complex shapes)
Partial Discharge Resistance	High	Very high	Medium

G10 epoxy laminated sheets

Typical Applications in Wind Turbine Generators

Application Area	G10	FR4	UPGM
Slot wedge	✔️	✔️ (Most widely used in wind power)	❌
Phase separators	✔️	✔️ (High arc resistance)	❌
End-winding support plate	✔️	✔️ (High strength + flame retardant)	✔️ (Used in cost-sensitive models)
Stator support / structural parts	✔️	✔️	✔️ (Common)
End blocks / spacers	✔️	✔️	✔️ (High volume, low cost)
Air-duct boards / insulation frames	✔️	✔️	✔️ (Lightweight + economical)
Offshore wind / high-humidity environments	✔️	Best choice	❌
High-voltage areas	High	Best	Weak
Cost-sensitive turbines	Suitable	Less economical	Most suitable

Selection Recommendations (Wind Power Industry)

1. Offshore wind turbines or high-humidity / salt-spray environments → FR4 is the best choice

Benefits:

Excellent flame retardancy (UL94 V0)

Very low water absorption

Highest mechanical strength

Outstanding moisture and partial discharge resistance

2. Onshore wind turbines with balanced cost and performance → G10

Suitable for:

Slot wedges

Phase insulation components

Structural insulation parts

It offers reliable performance with good cost-effectiveness.

3. Cost-sensitive applications, large structural parts & moderate electrical requirements → UPGM

Commonly used for:

Support frames

End-winding pressure plates

Non-high-voltage insulation structures

Advantages:

Low price

Easy machining

Adequate mechanical strength

Not recommended for high-voltage or partial-discharge-critical areas.

Insulation material manufacturer and quotation

XUJUE ELECTRICAL is a professional manufacturer of high-quality electrical insulation materials, integrating the research and development, production and sales of electrical and electrical insulation materials. It has more than 65 years of manufacturing experience. The production capacity and market share of insulation materials are ranked top three in the industry, and special insulation materials are ranked first. Products are exported to Europe, America, Southeast Asia and other countries and regions.

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