Application of G11 Epoxy Sheet in High-Voltage Motor Slot Wedges

Introduction to G11 epoxy sheet G11 epoxy glass fiber sheet is a high-performance insulating material made from wove...

Introduction to G11 epoxy sheet

G11 epoxy glass fiber sheet is a high-performance insulating material made from woven fiberglass cloth impregnated with epoxy resin and cured under high temperature and pressure. With a thermal class of H (180°C) and excellent electrical and mechanical properties, G11 is one of the most widely used materials for slot wedges in high-voltage motors (6 kV, 10 kV, 13.8 kV, etc.).

Slot wedges play a critical role in securing the stator windings inside the slots, maintaining mechanical stability, and preventing partial discharge. G11 offers a combination of strength + heat resistance + dielectric reliability, making it ideal for demanding motor environments.

1. Why G11 Epoxy sheet Is Ideal for High-Voltage Motor Slot Wedges

1.1 High Mechanical Strength

Flexural strength: 350–400 MPa
Excellent resistance to vibration and electromagnetic forces
Prevents coil movement and mechanical fatigue
This ensures long-term stability of stator windings during heavy load and start-stop cycles.

1.2 Excellent Electrical Insulation

Dielectric strength: ≥20 kV/mm
Strong resistance to partial discharge and electrical stress
Stable performance in high-voltage environments up to 13.8 kV
G11 helps reduce insulation failures at the coil-slot interface.

1.3 High Temperature Resistance (Class H 180°C)

Maintains mechanical integrity under high thermal loads
Low thermal aging rate
Performs well in motors operating under high-frequency starts and harsh environments
This gives G11 a clear advantage over G10, FR4, DMC, and polyester-based materials.

1.4 Low Water Absorption & Dimensional Stability

Water absorption ≤0.1%
Stable dimensions even in humid, oily, or high-temperature environments
Easy to machine into different slot wedge profiles
This ensures tight coil compression without expansion or deformation.

2. Typical Applications in High-Voltage Motors

2.1 Stator Slot Wedges for 6 kV, 10 kV, 13.8 kV Motors

G11 keeps windings firmly in the stator slots while resisting electrical, mechanical, and thermal stress.

2.2 Wind Turbine Generators

Requires high strength, humidity resistance, and thermal stability—G11 matches these needs perfectly.

2.3 Industrial High-Voltage Motors

Used in:
Pumps
Compressors
Fans
Mining motors
Petrochemical motors
These motors run in harsh conditions where G11 offers superior durability.

2.4 Motor Repair, Rewinding and Upgrading

Widely used in service centers as a replacement for:
Wooden wedges
DMC wedges
Standard epoxy sheets
G11 significantly enhances insulation reliability and motor lifespan.

3. Technical Specifications of G11 Slot Wedge Material

Property Typical Value
Composition Epoxy resin + fiberglass cloth
Thermal Class Class H (180°C)
Dielectric Strength ≥20 kV/mm
Flexural Strength 350–400 MPa
Water Absorption ≤0.1%
Machinability Good (cutting, CNC milling, chamfering)
Available Profiles Straight, dovetail, T-type, wave-shaped wedges
Customized shapes and sizes can be produced according to drawings.

4. Advantages of Using G11 for Slot Wedges

Improves overall insulation system of the motor
Enhances coil fixation, reducing vibration and abrasion
Extends motor service life under high voltage and high temperature
Stable performance in humid or chemically aggressive environments
Excellent mechanical stability and precise dimensions
These advantages make G11 a preferred material for modern high-voltage motor manufacturers and maintenance providers.

5. Alternative Materials (When Appropriate)

Material Notes
G10 Lower thermal rating; suitable for medium-voltage motors
FR4 Good electrical properties but lower heat resistance
DMC wedges Cost-effective but not suitable for severe thermal cycles
Phenolic laminate Lower mechanical strength and aging resistance

For mission-critical applications, G11 is the superior choice due to its balanced performance.

If you are looking for G11 epoxy fiberglass sheets, please contact Xujue Electrical and provide the product specifications, thickness and purpose you need, you can get detailed product information and quotation, and also send samples free of charge