AMA Insulation Paper Composition and Selection Guide

Time: 11-05 2025 Auther: Xujue Electrical

1. Structure and Features of AMA Insulation Paper AMA insulation paper (Aromatic polyamide paper + Polyester film + ...

1. Structure and Features of AMA Insulation Paper

AMA insulation paper (Aromatic polyamide paper + Polyester film + Aromatic polyamide paper) is a three-layer composite insulation material commonly used in transformers, motors, and inductors.

Structure:

A (top layer): Aramid paper (Nomex)
M (middle layer): Polyester film (PET)
A (bottom layer): Aramid paper (Nomex)

Features:

Excellent thermal and electrical insulation from aramid paper

Good mechanical strength and toughness from polyester film

Typical thermal class: F (155 °C) or H (180 °C)

AMA insulation paper

2. Common Models and Characteristics

Model	Structure (mm)	Thermal Class	Features	Typical Application
AMA 0.15	0.05A + 0.05M + 0.05A	F/H	Flexible, easy to form	Slot insulation for small motors
AMA 0.20	0.05A + 0.10M + 0.05A	F/H	Balanced performance	General purpose
AMA 0.25	0.075A + 0.10M + 0.075A	H	Higher strength	Slot and interlayer insulation
AMA 0.30–0.40	0.10A + 0.15M + 0.10A	H	Strong compressive strength	Layer insulation in dry-type transformers
AMA 0.50+	Custom	H	Very high strength	End or spacer insulation for large transformers

3. Key Selection Principles

Based on Application Position

Application	Recommended Model	Description
Motor slot insulation	AMA 0.15–0.20	Requires flexibility and formability
Slot liner or end insulation	AMA 0.20–0.25	Balance of mechanical and electrical properties
Dry-type transformer interlayer insulation	AMA 0.25–0.40	High dielectric strength and durability
Transformer end or spacer insulation	AMA 0.40–0.50	Strong mechanical and compressive strength

Based on Operating Temperature

≤ 155 °C → Choose F-class AMA

≤ 180 °C → Choose H-class AMA

For long-term high temperature and high voltage → Choose H-class, thicker structure

Based on Voltage Level

Voltage	Recommended Thickness
≤ 1 kV	0.15–0.20 mm
1–10 kV	0.25–0.40 mm
≥ 10 kV	≥ 0.40 mm or multi-layer laminated use

Based on Mechanical Requirements

For high mechanical strength (e.g., end insulation, spacers) → use thicker AMA (0.30–0.50 mm)

For flexibility and forming (e.g., slot or corner insulation) → use thin AMA (0.15–0.20 mm)

4. Common Brands

DuPont NOMEX series (high-end international brand)

Baoke, Huawei, Southern Electrical Materials, Jinzhang Tech (cost-effective domestic brands in China)

Typical product labels: AMA-HA, AMA-F, Nomex-Film-Nomex composites

5. Summary of Selection Rules

If you’re unsure which model to choose, use this simple rule:

Application + Temperature Class + Required Thickness → AMA Model

Examples:

Small motor slot insulation (155 °C) → AMA 0.20 F-class

Dry-type transformer interlayer (180 °C) → AMA 0.30 H-class

High-voltage transformer end insulation (180 °C) → AMA 0.50 H-class

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