Why is GPO-3 the preferred material for electrical insulation?

Keywords: GPO-3 sheet, electrical insulation material, glass fiber reinforced polyester, UL 94 V-0, high dielectric s...

Keywords: GPO-3 sheet, electrical insulation material, glass fiber reinforced polyester, UL 94 V-0, high dielectric strength

What is GPO-3?

GPO-3 is a glass fiber reinforced unsaturated polyester laminate with excellent electrical insulation, flame retardancy, mechanical strength, and environmental resistance. GPO-3 has become a widely used thermoset insulation material in industries such as power, electrical equipment, and new energy.
GPO-3 sheet (Glass Polyester Sheet, Grade 3) is widely considered the preferred material in the electrical insulation field, primarily due to its unique combination of properties that perfectly meet the high insulation requirements of electrical equipment. The following are its key features and reasons for its preference:

Excellent electrical insulation properties:

High dielectric strength: It can withstand extremely high voltages without breakdown (typically 20 kV/mm or higher), ensuring safe operation of equipment under high voltage.

High Volume and Surface Resistivity: Offers extremely high resistance in both dry and humid environments, effectively preventing current leakage.
Low Dielectric Constant and Dissipation Factor: Low dielectric loss, low heat generation, high efficiency, and minimal signal distortion are achieved in high-frequency applications (such as motors and switchgear).

High Comparative Tracking Index: Excellent resistance to carbonized conductive paths formed by surface current leakage in humid and dirty environments (typically CTI ≥ 600V), which is critical for outdoor equipment, highly polluted environments, or compact designs.

Excellent Mechanical Strength and Rigidity:

Reinforced with alkali-free glass fiber cloth, it imparts exceptional mechanical strength, rigidity, and dimensional stability.

Withstands significant mechanical stress, shock, and vibration without deformation or cracking, ensuring long-term structural integrity in applications such as switchgear, support structures, and slot wedges.

Excellent Heat Resistance:

Has a high continuous operating temperature rating (typically 155°C or F-Class, with some high-performance models reaching 180°C or H-Class). It maintains excellent electrical and mechanical properties even in high-temperature environments, making it suitable for heat-generating components such as motors, transformers, and reactors.

Excellent flame retardancy and arc resistance:

Meets the stringent UL 94 V-0 flame retardancy rating, is self-extinguishing, and will not burn easily in the event of a fire, effectively preventing the spread of flames.

It exhibits high arc resistance and arc tracking resistance, withstanding arc shocks generated during switching operations or faults without forming conductive carbonization paths. This is crucial to the safety of critical components such as switch contacts and arc extinguishing chambers.

Excellent chemical and environmental resistance:

It exhibits excellent resistance to most chemicals, including acids, alkalis, solvents, and oils, and is not susceptible to corrosion or degradation.

Resistant to moisture, weathering, and UV rays (select models), it is suitable for a variety of indoor and outdoor environments and harsh working conditions.

Excellent processability:

It offers excellent machinability (can be sawed, drilled, turned, milled, and stamped) and formability (can be bent and shaped under heat).

Easy to cut into various complex shapes to meet the structural design requirements of various electrical components.

Low Smoke and Non-Toxic (Select Models):

Produces low smoke and toxic gases during combustion (meets specific standards such as NEMA LI 1), enhancing personnel safety and environmental protection.

Why is it the preferred choice?

GPO-3 successfully combines key properties: high electrical insulation, high strength, high heat resistance, high flame/arc resistance, good weather and chemical resistance, and easy processability. This comprehensive performance balance is rare among electrical insulation materials:

Safety and Reliability: High dielectric strength, high CTI, and high flame/arc resistance ensure the safety of equipment and personnel.

Stable and Long-Lasting Performance: High temperature, chemical, and environmental resistance enable long-term stable operation even in harsh conditions, extending equipment life.

Design Flexibility: Excellent mechanical properties and processability enable the design of more compact and complex insulation structures.

Wide Application: Suitable for low to high voltage, indoor and outdoor environments, and from standard environments to high temperature, high humidity, and high pollution environments.

GPO-3 vs. Other Insulation Materials

Typical Applications:

Motors and Generators: Slot wedges, phase insulation, end liners, supports, and insulating bushings.

Switchgear: Partitions, support insulators, arc extinguishing chamber components, and operating mechanism insulation.

Transformers and Reactors: Insulation spacers, end insulation, stays, and lead wire supports.

Electrical and Electronic Equipment: Terminal blocks, terminal strips, relay bases, and transformer bobbins.

Rail Transit: Traction motors and auxiliary converter insulation components.

Renewable Energy: Wind turbine insulation components.

Industrial Equipment: Controllers and switchboard insulation components.

Therefore, when the design and application of electrical equipment requires an insulation material that simultaneously meets high electrical performance, high mechanical strength, high heat resistance, and high flame retardancy and arc resistance requirements, GPO-3, with its unparalleled comprehensive properties, naturally becomes the preferred solution for engineers and designers.