Types of insulation paper for generators and how to select them

Insulation paper for generators is mainly used for winding insulation, interlayer insulation and slot insulation to e...

Insulation paper for generators is mainly used for winding insulation, interlayer insulation and slot insulation to ensure the safety and reliability of motors or generators under high voltage, high temperature and long-term operation conditions.

1. Comparison Table of Insulation Paper Types for Generators

2. Guidelines for Selecting Insulation Paper

Select by Temperature Class

Class B (130℃), F (155℃), H (180℃), >220℃.

Generator operating temperature ≤ insulation paper temperature class × safety factor (typically 1.2–1.3).

Select by Application Location

Slot insulation: Choose paper with good flexibility and elongation, e.g., Crepe Paper or pre-impregnated DMD.

Inter-layer insulation: Choose paper with high mechanical strength and heat resistance, e.g., NMN, AMA, or DMD.

End support / stator slot wedges: Use phenolic tube/fabric tube for mechanical support.

Select by Operating Environment

High temperature, high humidity, or corrosive environments → AMA or DMD.

General industrial environment → NMN is sufficient.

Consider Mechanical Processing

For thick sheets or complex winding shapes → pre-impregnated DMD and Crepe Paper are easier to process and reduce stress concentration.

Consider Cost-effectiveness

Ordinary low-voltage windings → NMN is the most economical.

High-temperature or high-reliability windings → AMA or DMD, although more expensive, offer longer life and higher reliability.

Summary of Selection Strategy:

1.Determine the generator’s operating temperature and insulation class → choose paper with suitable temperature rating.

2.Select material based on location (slot, inter-layer, end support) → flexible or mechanically strong paper as appropriate.

3.Combine environmental conditions and cost → finalize material choice.