White DMD and Red Prepreg DMD Procurement Guide

In the manufacture of transformers, motors, and other electrical equipment, DMD insulation materials are widely used for interlayer, inter-slot, and inter-phase insulation due to their excellent electrical properties and mechanical strength. In actual procurement, white DMD and red prepreg DMD are two commonly used types, with significant differences in structure, temperature resistance rating, and applicable scenarios. This article provides a practical procurement reference from the aspects of material performance, applicable scope, and key procurement points.

Overview of DMD Insulation Materials

DMD insulation material is a three-layer structure product composed of polyester film (PET) and two layers of non-woven fabric, possessing excellent dielectric properties and mechanical strength. It is suitable for various medium and low voltage electrical equipment. Based on whether it has undergone resin pre-impregnation treatment, DMD can be divided into two categories: white DMD and red prepreg  DMD.

Features and Applications of White DMD

Main Features:

Insulation class is generally B (130℃)

Good flexibility, easy to cut and process

Low cost

Suitable for electrical equipment with general temperature rise requirements

Typical Applications:

Interlayer insulation of small and medium-sized transformers

Slot insulation of low-voltage motors

General industrial electrical equipment

White DMD is suitable for scenarios with stable operating temperatures and low insulation class requirements.

Features and Applications of Red Prepreg DMD

Main Features:

More stable structure due to resin pre-impregnation

Insulation class is generally F (155℃)

Higher heat resistance and mechanical strength than white DMD

More reliable performance under high temperature and high load conditions

Typical Applications:

Winding insulation of dry-type transformers

High-load motors and generators

Electrical equipment with high requirements for temperature resistance and service life

Red prepreg DMD is suitable for scenarios with long-term high-temperature operation or harsh environmental conditions.

White DMD and Red Prepreg DMD Procurement Considerations

1. Technical Parameter Confirmation

Certifications and Standards: Check if the material has UL certification and complies with relevant standards such as GB/T 5591.3 and IEC 60394.

Performance Testing: Request the supplier to provide recent third-party testing reports, focusing on key indicators such as breakdown voltage and heat index (TI).

2. Supplier Evaluation

Production Capacity and Quality Control: 

Understand the supplier's production equipment level, such as coating precision and curing control.

Confirm their quality management system, such as whether they are ISO9001 certified.

Technical Support and Service: 

Assess the supplier's ability to provide application guidance and problem-solving.

Understand whether they can provide customized services, such as special widths, thicknesses, or performance adjustments.

3. Cost and Supply Chain

Price Analysis: 

Pay attention to the impact of raw material price fluctuations on the product.

Understand the minimum order quantity and bulk discount policy.

Logistics and Inventory: 

Confirm the supplier's delivery cycle and on-time delivery record.

Understand their inventory strategy and emergency supply capabilities.

Common Procurement Misconceptions and Recommendations

Misconception 1: Judging Material Performance Solely by Color

Recommendation: Request detailed technical data sheets and select based on actual performance parameters, not appearance.

Misconception 2: Overly Pursuing Low Prices

Recommendation: Consider the total cost of ownership and the impact of material performance on equipment reliability.

Misconception 3: Ignoring the Actual Operating Environment

Recommendation: Select the appropriate material type based on the temperature, humidity, and chemical environment of the operating equipment.

White DMD and red prepreg DMD each have their applicable scenarios. When purchasing, a comprehensive selection should be made based on actual needs, performance requirements, and cost budget. It is recommended to fully understand the material characteristics before purchasing, conduct necessary testing and verification, and choose suppliers with technical capabilities and quality assurance.

For specific procurement needs, consult professional insulation material suppliers or technicians for targeted selection advice and market information.

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