Characteristics of epoxy pre-impregnated DMD insulation material for dry-type transformers

1. Material structure and process characteristics

Reasonable layered structure: The DMD in the name corresponds to a three-layer structure - with polyester fiber non-woven fabric on both sides (D) and polyester film in the middle (M), combined with impregnated epoxy resin, it has both mechanical strength and insulation properties.

The advantages of curing are obvious: epoxy resin contains active groups such as epoxy and amine groups, which can be quickly cured at medium and high temperatures. During curing, almost no low molecular weight volatiles are discharged, ultimately forming an insulation structure with extremely low shrinkage rate, avoiding insulation layer void defects.

Excellent bonding performance: High bonding strength to copper foil and aluminum foil, with a tensile shear strength of ≥ 3.0MPa, and no delamination or detachment after wrapping and curing.

2. Core performance characteristics

Excellent electrical insulation performance: breakdown voltage ≥ 7.0-10kV, temperature index up to 155 ℃, meeting F-level heat resistance requirements, with excellent flame retardancy, meeting the requirements for safe operation of transformers.

Good storage stability: It has a long shelf life under different storage conditions. It can be stored for a long time at room temperature (20 ℃, 50% humidity), and can also ensure a shelf life of 6-12 months when stored at low temperatures. It can still be used after passing the inspection if it exceeds the shelf life.

The finished product is in a uniform and stable state: the surface of the product is flat, the resin distribution is uniform, and it will not damage the surface during unwinding. There are no defects such as folds, bubbles, impurities, etc. that affect the insulation performance.

Strong processability: The conventional thickness covers 0.12mm-0.50mm, and can be cut into any width according to needs, suitable for processing transformer coils of different specifications.

3. Application adaptation characteristics

As a specialized interlayer insulation material for low-voltage coils of dry-type transformers, it is fully compatible with foil winding and wire winding processes, and can also be extended for inter-slot, inter-turn, and inter-phase insulation of reactors and F-class motors. It is currently the mature and stable preferred material for insulation systems of dry-type transformers.