DMD Insulation Paper: Temperature Classes and Key Applications

1. Definition and Structure of DMD Insulation Paper DMD insulation paper is a high-performance flexible composite in...

1. Definition and Structure of DMD Insulation Paper

DMD insulation paper is a high-performance flexible composite insulation material widely used in motors, transformers, and various electrical equipment. It is produced by laminating polyester film (M) between two layers of polyester non-woven fabric (D + D) using high-temperature adhesive.
This three-layer structure combines excellent mechanical strength, electrical insulation, and thermal resistance, making DMD one of the most commonly used Class B and Class F insulation materials.

DMD insulation paper

2. Temperature Class of DMD Insulation Paper

1) Standard thermal class: Class B (130°C)

Most industrial-grade DMD insulation materials conform to the Class B, 130°C thermal rating.
Suitable for general-purpose motors, distribution transformers, and standard slot insulation applications.

2) High-temperature DMD: Class F (155°C)

By enhancing resin systems and the polyester film, DMD can achieve a Class F, 155°C temperature rating.
Ideal for higher-load equipment, higher temperature rise, and long-term continuous operation.

3) Thickened or reinforced DMD

Some manufacturers offer:
H-class (180°C) composite insulation
Resin-coated DMD (suitable for automatic slot-liner forming)
However, B-class and F-class remain the mainstream thermal classes for standard DMD materials.

Pre-impregnated DMD insulation paper

3. Typical Applications of DMD Insulation Paper

1) Motor industry (largest consumption area)

Slot insulation
Slot liner and wedge insulation
Phase insulation
End-winding insulation
Applicable to: AC motors, induction motors, household motors, pump motors, and fan motors.

2) Transformer industry

Interlayer insulation for dry-type transformers
Insulation between core and coils
Filling and support insulation
Low-voltage coil insulation layers
Common in dry-type transformers, control transformers, and small distribution transformers.

3) Electromagnetic coil manufacturing

Coil wrapping
Layer insulation
Formed insulation components
Typical in: solenoids, welding transformers, charging equipment, industrial coils.

4) Maintenance & insulation reinforcement

Motor repair slot liners
Transformer winding repair
On-site dielectric strength reinforcement

4. Common Specifications of DMD (for quotation or product page use)

Thickness: 0.10 / 0.13 / 0.15 / 0.18 / 0.20 / 0.25 / 0.30 mm
Width: Standard 1000 mm (custom slitting available from 5–1000 mm)
Color: White, blue, yellow (color differences do not affect performance)
Dielectric strength: ≥ 4–6 kV (varies by thickness)
Basis weight: 120–220 g/m²

Xujue Electrical is a professional manufacturer of transformer and motor insulation materials with more than 65 years of manufacturing experience. If you need more DMD product information and quotes, please contact us.