Polifibra Markets Innovative and Revolutionary ‘EV-Tubes’

14.07.2024 - Polifibra’s Italian partner Politubes has developed a revolutionary solution in order to improve the thermal management as well as the insulation of electric motors. They call this solution ‘EV-Tubes’. These spiral insulation hoses are used for ‘hairpin’ copper windings in electric motors and generators. They ensure improved and more efficient motor performance thanks to their thermal as well as insulating properties. They also protect the wire connections from overheating and mechanical damage. EV-Tubes developed by Politubes are specifically designed for 400 or 800 V and other electric motors and meet the latest technological developments in the sector of e-mobility. Polifibra Folien GmbH markets EV-Tubes and custom fits them to customer requirements.

For electric motors, Politubes recommends multi-layer EV tubes or spiral hoses made from the materials Nomex/Kapton/Nomex (NKN). They are thinner than conventional insulating tapes and manufactured in thicknesses between 0.13 mm and 0.23 mm without overlap. The reduction in thickness enables an improvement in the copper filling factor inside the stator slot of the motor. As a result torque and motor performance is improved. They also reduce heat peaks and partial discharges, ensuring a longer service life of the motor. The hermetic seal of EV-Tubes prevents vibrations from causing slight displacement of the insulating tape, which may lead to partial discharges, over time.

Advantages of Insulating Hoses

The reduction in thickness and the lack of tape overlap stem from the considerable advantages of EV-Tubes in the area of application:

• Improved thermal conductivity and heat dissipation within the stator slot in the motor housing
• Reduction of dangerous heat peaks that may affect rotors
• Reduced risk of damaging overheating of the engine
• Reduction of partial discharges through hermetic tube sealing
• Higher level of electrical insulation than conventional tapes, where the area of overlap is open consequently being the weakest part in the insulation chain
• Reduced risk of insulation displacement
• Improved and more uniform thermal, electrical and chemical insulation
• Excellent waterproofing properties by use of conventional resins
• The lack of overlap reduces the risk of jamming when inserting hairpins into the stator slots
• Reducing the risk of insulation displacement when bending hairpins
• Improved mechanical tensile strength

Process automation companies around the world already offer fully automated systems for inserting EV-tubes into stator slots. For automotive applications, Politubes also supplies ultrasonically welded caps made of a combination of Nomex 411 and heat-shrinkable polyester, which are used to insulate joints, motor cable connections and other components, ensuring uniform insulation throughout the system.

If you have any questions about insulating hoses and caps for use in the electrical sector, we are happy to answer them. We are looking forward to hearing from you.

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