If you already know NMN y DMD, the next question is almost always NHN. These three flexible composites cover the full thermal ladder for transformer and motor insulation — yet they are easy to confuse on a datasheet because the names differ by a single letter and the structures look alike. This guide completes the picture started in our NMN vs DMD comparison: what NHN actually is, how it sits above NMN and DMD, and how to pick the right grade without over- or under-buying.
What Flexible Composite Insulation Is — in One Line
A flexible composite bonds a thin dielectric film between two outer layers of non-woven or aramid paper. The film carries the dielectric strength; the outer layers add mechanical toughness, absorb impregnating varnish, and survive winding stress. The three-letter code describes the stack — and the stack, especially the core film, decides the temperature class. (For the DMD-vs-NMN basics, see the NMN vs DMD guide.)
DMD: The Class B/F Baseline
DMD = Dacron – Mylar – Dacron — two polyester non-woven layers around a polyester (PET) film core.
- Clase térmica: Clase B (130 °C) hasta Clase F (155 °C) para las versiones de grado F.
- Tensión de ruptura: ~8–15 kV/mm
- Costo: el más bajo de los tres
- Ideal para: general-purpose motors, oil-immersed and dry-type transformer layer/phase insulation, standard industrial equipment below 155°C
DMD is the default when the application sits comfortably below 155°C and budget leads. It handles impregnation well and is widely stocked, which keeps lead times short. See the DMD product page for grades and thicknesses.
NMN: The Class F/H Upgrade
NMN = Nomex – Mylar – Nomex — aramid paper outer layers around the same PET film core.
- Clase térmica: Clase F (155 °C) hasta Clase H (180 °C)
- Tensión de ruptura: ~12–20 kV/mm
- Costo: moderado (típicamente 20–30% por encima de DMD)
- Ideal para: dry-type (cast-resin) transformers, traction and wind generators, higher-temperature motors, anywhere edge-tear and chemical resistance matter
The aramid outer layers are what you pay for: superior thermal aging, better puncture and tear resistance, and stable performance under thermal cycling. When a design pushes toward or past 155°C, NMN is the natural step up from DMD. Full details on the NMN product page.
NHN: The Class H/C Top Tier
NHN = Nomex – polyimide – Nomex — aramid paper outer layers, but with a polyimide (PI) film core instead of PET.
- Clase térmica: Class H (180°C) up to Class C (200–220°C)
- Tensión de ruptura: high, with excellent high-temperature retention
- Costo: highest of the three
- Ideal para: EV traction motors, wind and hydropower generators, aerospace, and any duty that runs hot or cycles hard
The polyimide core is the whole point: it keeps its dielectric and mechanical properties far above where PET film would soften. NHN is the grade you reach for when NMN’s ceiling is not enough. See the Página de producto NHN.
NHN vs NMN vs DMD: Side-by-Side
| Propiedad | DMD | NMN | NHN |
|---|---|---|---|
| Capas exteriores | Polyester non-woven | Nomex aramid | Nomex aramid |
| Película principal | Polyester (PET) | Polyester (PET) | Polyimide (PI) |
| Clase térmica | B (130°C) – F (155°C) | F (155°C) – H (180°C) | H (180°C) – C (200–220°C) |
| Voltaje de ruptura | ~8–15 kV/mm | ~12–20 kV/mm | High, heat-stable |
| Tear / puncture | Bien | Superior | Superior |
| Costo relativo | Bajo | Medio | High |
| Uso típico | Motores estándar, transformadores generales | Transformadores de tipo seco, tracción, motores de alta temperatura | EV traction, wind/hydro, aerospace |
The takeaway: DMD, NMN, and NHN are rungs on one ladder, separated mainly by the core film and therefore by the temperature class.
Cómo elegir: Tres reglas
- Let the hottest spot set the class. Under ~155°C, DMD is usually enough. Cross 155°C and NMN becomes the safe spec. Past 180°C, or under hard thermal cycling, step to NHN.
- Adapta la tarea a la situación, no al catálogo. A standard LV motor does not need NHN; an EV traction motor does not want to save on a composite that will age early. Specify to the real thermal and mechanical demand.
- Watch thickness separately. All three come in 0.10–0.50 mm ranges. Slot-fill and creepage distance still have to be met — grade and thickness are separate decisions.
Errores comunes en las especificaciones
- Especificación excesiva: putting NHN in a 120°C appliance motor just because it is “best.” You pay for temperature margin you never use.
- Especificación insuficiente: running DMD where the hotspot reaches 170°C. The composite ages early and you trade a small saving for field failures.
- Confusing NMN and NHN: both are Nomex-faced, but only NHN has the PI core. If the datasheet does not state the core film, ask — the class depends on it.
Conclusión
DMD, NMN, and NHN are not competitors so much as a thermal ladder: DMD for standard Class B/F duty at the best price, NMN for F/H margins, NHN for H/C and the hottest, hardest-cycling duty. Pick by operating temperature and real duty, and you get reliability without paying for unused headroom. Browse the full range in our Categoría de aislamiento compuesto flexible.
¿Necesita ayuda para especificar el material compuesto adecuado para su transformador o motor? Contacta con nuestro equipo En función de la clase de temperatura y la aplicación, adaptaremos el grado y el grosor a su construcción.
Lectura relacionada: NMN vs DMD: Cómo elegir el aislamiento compuesto flexible adecuado
Explora todos los materiales compuestos flexibles: Categoría de aislamiento compuesto flexible