mica tapes


The efficiency and service life of an electrical machine depends to a large extent on the insulation system. In order to extract maximum performance from this system, we rigorously pursue a system approach.

Our comprehensive portfolio of insulating tapes ranges from mica-based conductor insulation to main insulation and corona protection with conductive and semi-conductive tapes.

In combination with specifically developed resin systems, this results in highly resistant and durable insulation systems. These are ideally suited to withstand all electrical, mechanical, thermal, and environmental stresses occurring over the entire service life, thus guaranteeing safe, fault-free operation.

To guarantee the excellent quality of our products, we master the complete value chain from mica mining and resin development on the raw material side to ready-to-install winding components from our coil shop in India.

Our comprehensive expertise for material, insulation system and coil enables us to continuously optimize and develop our system offering.

PRODUCTS & SOLUTIONS: Electrical insulation

The task of the main wall insulation is to separate the coil or bar winding of the electrical machine, which consists of individual live conductors. For this purpose, the mica tapes are wound onto the coils or bars in several layers, either manually or by machine.

We are the pioneers of modern mica tapes for both the Resin Rich (RR) and Vacuum Pressure Impregnation (VPI) processes. Both processes produce high quality, cost effective main wall insulation with extreme resistance to electrical discharge, due to our proprietary mica paper combined with mechanically robust carrier materials and various resin systems.

While Resin Rich Systems combine the advantage of low costs with a high flexibility in the service business for small and medium sized electrical machines, VPI insulation systems show their advantages especially in high volume applications.

With both technologies, the main wall insulation produced with our systems is characterized by the following properties:

  • high dielectric strength
  • high partial discharge resistance
  • wrinkle-free banding
  • suitable for manual and machine processing
  • full compatibility with predefined resin systems
  • applicable for conventional and flat coil technologies
  • With Samicapor®, Von Roll has developed a range of outstanding vacuum pressure impregnating mica tapes (VPI) that are fully compatible with specially developed or predefined resin systems.

Under the brand name Samicatherm® we offer a comprehensive range of Resin Rich (RR) tapes and systems as the main wall insulation for both conventional and hydrostatic pressing processes.

Especially for the insulation of end-windings, we have developed mica tapes under the names Filosam® and Samicaflex®, which ensure a certain mechanical flexibility during installation and operation.

Targeted control and distribution of electrical stresses within the electrical machine are an essential design component of any high voltage machine to prevent damage during high voltage testing and operation, and to ensure the service life of the entire insulation system.

Von Roll has developed conductive and semiconductive tapes with different control characteristics. CoronaShield® C serves as outer corona protection with constant resistance to prevent discharges inside the stator slot; CoronaShield® SC as end winding corona protection with voltage-dependent resistance for targeted field control at the slot exit.

The task of conductor insulation is to separate the individual live conductors from each other. For this, our mica tapes are wound onto the conductor by machine.

Depending on the application, our Samicafilm® products consist of various combinations of mica papers, carrier films, and bonding resins matched to the application. The carrier films are optionally coated with a hot melt adhesive. The use of our Samicafilm® tapes as preferred conductor insulation for stator and rotor coils offers the following advantages:

  • very high partial discharge resistance, especially under impulse stresses and in converter operation
  • lower insulation thickness
  • higher flexibility and shorter delivery times

The outstanding thermal properties of the non-combustible mineral mica enable the use of mica tapes for fire-resistant cables in safety-relevant building installations that save lives in the event of fire.

Our Cablosam® mica tapes enjoy an excellent reputation worldwide. They are specifically designed for our customers’ taping technologies and are the preferred choice for meeting stringent international standards. Cablosam® tapes are also free of halogens and do not release toxic fumes.

  • Insulating systems for high-voltage rotating machines

    Von Roll is committed to creating added value for its customers with the insulating materials and processes used in state-of-the-art electrical high-voltage motors as well as small generators with similar design. We offer the solutions you need for higher performance and reliability together with low manufacturing costs.

    No matter what the precise requirements of your machines, we have materials that will suit them using either resin-rich (RR) or vacuum pressure impregnation (VPI) technologies.

    Cover der Broschüre "Insulating systems for high voltage rotating machines"
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