Insulation class B
Class B insulation material
Class B insulation material consists of materials or combinations of materials such as polyester film , Glimmer , fibreglass, etc. with suitable adhesive, impregnation or coating materials (note some older applications use asbestos). Other materials or combinations of materials, not necessarily inorganic, may be included in this class if experience or testing shows that they can be operated at the Class B temperature.
Maximum allowable temperature: (IEC60034-1 & NEMA MG1-12.43): 130C, 266F.
Class B materials
In the area of insulation class B, we focus on 4 materials:
- branded polyester film Mylar A and Hostaphan WN
- Pressboard-polyester-foil-pressboard laminate
- grained PSP-PET-PSP laminate
- Polyester- nonwovens (Freudenberg Viledon H1010, Viledon H1015, Viledon H1030)
Mylar A and Hostaphan WN brand polyester film
Mylar A is a transparent, flexible, strong, tough and durable polyester film based on polyethylene terephthalate (PET). Mylar A is milky opaque in thicknesses from 75 µ. Excellent resistance to moisture and most chemicals. Since it does not contain any plasticizers, the polyester film does not become brittle due to aging under normal conditions. With a thickness of 0,500 mm, Mylar 500A also offers exceptionally high strength values. Because of its mechanical strength, Mylar A 500 is particularly useful as wedges for motor insulation, stampings, and semi-rigid or rigid printed circuit boards
Hostaphan WN is a white polyethylene terephthalate (PET) film that is particularly suitable for the electrical insulation of machines and devices such as electric motors and generators. The film is characterized by a high dielectric strength and a high volume resistance.
All polyester films are suitable for use as slot insulation protective glass and phase insulation in motor and generator construction and when used as core, layer and deck insulation in transformers, reactors and relays
Pressboard-polyester-foil-pressboard laminate
This class B electrical insulating material is a 3-layer laminate consisting of polyester film with pressboard on both sides. This laminate has proven to be extremely tear-resistant and is characterized by high dielectric strength.
The pressboard layer absorbs the impregnating agents used in engine construction very well and thus prevents unfavorable air pockets. This leads to improved heat dissipation from the winding copper to the iron core.
These laminates are suitable as slot insulation and slot covers in electric motors and as layer and core insulation in transformer construction
grained PSP-PET-PSP laminate
2-ply or 3-ply material (depending on type) with an inner layer of polyester film and outer layers of grained (roughened) green or brown pressboard. These properties provide good flexibility and elasticity while maintaining a certain minimum strength. The minimum strength is required to be able to push the phase insulation between the windings. Flexibility prevents damage from mechanical stress when the end winding is deformed. This product is also available as a self-adhesive die-cut.
Polyester nonwovens (Freudenberg Viledon H1010, Viledon H1015, Viledon H1030, Viledon H 1062)
This product is a thermally bonded polyester fleece with a high degree of impregnation and impregnation and good mechanical properties. The combination of low moisture absorption, good compatibility with resins and paints, chemical purity, low dielectric losses, high continuous temperature resistance and long service life makes it an ideal candidate for use as phase insulation.
