Insulation class F

Isolierstoffklasse F insulation class

Insulation class F

Insulating material class F

Class F insulating material consists of materials or combinations of materials such as mica, fiberglass, etc., with suitable binders, impregnating or coating materials, and other materials or combinations of materials, not necessarily inorganic, that have been shown by experience or testing to be capable of operating at the Class F temperature (materials with a degree of thermal stability that allows them to operate at a temperature 25 degrees higher than Class B materials).

Maximum Allowable Temperature: (IEC60034-1 & NEMA MG1-12.43): 155C, 311F.

Materials class F

We focus on 2 materials in the insulation class F area:

  1. DMD laminates
  2. NMN laminates

DMD Laminate: Insulation Class F

DMD is a 3-layer laminate consisting of polyester fleece – polyester film – polyester fleece, where the polyester fleece is optionally additionally impregnated or coated to be able to achieve a higher thermal class.

DMD is therefore available in thermal classes B and F, depending on the manufacturer and impregnation. If the material is uncoated, we sell it only as class B. DMD has a high mechanical stability and at the same time a high dielectric strength. Its smooth surface makes it easy to machine and feed into the rotor or stator.

DMD laminates form a very good bond with impregnating and trickling resins due to the special outer layer of nonwoven. This is the prerequisite for a permanently stable insulation system. Depending on the structure of the laminate, i.e. the individual material thicknesses of nonwoven and polyester film, there are various overall thicknesses for DMD ranging from 0.09 to 1.20 mm.

We also use this laminate for the production of stamped parts as well as formed parts such as slot closures and slot insulations. The DMD is also supplied feathered edged.

NMN laminate: a class F laminate

NMN is a laminate consisting of 3 layers: 1st layer Nomex, 2nd layer polyester film, 3rd layer Nomex. For standard NMN laminates, calendered Nomex® aramid paper type 464 or 416 is used. In NMN laminates, the good mechanical and electrical properties of polyester films are ideally complemented by the excellent thermal properties of Nomex® – aramid paper. We offer three main types of NMN laminates:

NMN 5 – Nomex layer: 50 µm
NMN 8 – Nomex layer: 80 µm
NMN 13 – Nomex layer: 130 µm

Depending on the thickness of the polyester film, this results in total thicknesses of 0.12 to 0.82 mm. Special laminates for slot closures are also manufactured in greater thicknesses.

NMN laminates are frequently used as insulation material in electric motor construction. The combination of the extremely heat-resistant Nomex paper and the dimensionally stable polyester film is ideal for use as slot insulations, phase insulations, stamped parts or slot closures.

NMN laminates are also available in the Nomex® 411 version, i.e. a 3-ply laminate with uncalendered Nomex® 411 aramid paper. This material is then used as phase insulation.


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