Insulation materials for transformers winding

To ensure reliable and continuous exploitation of electrotechnical, radio engineering and electronic devices many developers pay special attention to the choice of insulation materials. At present time in the market there is a wide range of insulating tapes and glass fabrics which differ from each other by electrical, mechanical and chemical properties. Among important characteristics of such materials one can noted:

high dielectric strength
electrical resistivity
permittivity
dielectric loss

Furthermore, when designing winding components for various purposes especially important properties of the insulating materials are the mechanical strength, flexibility, elasticity, heat and frost resistance in a wide temperature range, hygroscopicity, chemical resistance to solvents and other. For example, when choosing a tape it is recommended to take into a consideration the operating temperatures specified in the table. The using of the corresponding tape's class will provide a work of a whole device for 20,000 hours.

Insulation class	Rated temperature
Y	90°C
A	105°C
B	130°C
F	155°C
H	180°C
C	200°C

Insulating self adhesive tapes are widely used in a winding production for the following operations:

interwinding insulation performance
interlayer insulation materials fixing
turns mounting
external insulation of winding
cores fixing during assembling
electrical safety increasing
design of marketable style for transformers

As adhesives electric tapes can be used:

A - acrylic adhesive. It has chemical resistance to solvents and resistance to aging up to 155°C.
AT - acrylic-thermosetting adhesive
AS - acrylic adhesive with silver particles
R - rubber (natural). In conditions of constant temperature maintenance its value must not exceed 130°C
RT -natural rubber thermosetting
RTF - rubber fire-resistant thermosetting adhesive
Si - silicone adhesive
SiT - silicone thermosetting adhesive

As a insulating tapes base may be used: polyester; fiberglass; polyester reinforced with glass filaments; laminates based on polyester and others.
According to consumers request an electrical tape can be cut to any desired width.

Polyester tape

Polyester is characterized by improved insulating properties and a defined permeability at film thickness 25 microns. The using of an acrylic adhesive provides resistance to solvents and chemical environments.

Polyester tape
Insulation class B 130°C
Series	Backing	Adhesive	Backing thickness, mm	Total thickness, mm	Color	Adhesion to steel, N/25mm	Tensile strength, N/25mm	Elongation, %	Dielectric strength (VDE 0303)	Read more
R31	polyester film	RT	0.025	0.051	Yellow	12.30	110.0	100	5000
54113	polyester film	AT	0.025	0.060	Clear	12.30	110.0	100	5000
54143	polyester film	AT	0.035	0.076	Clear	13.70	166.0	100	7500

Polyester tapes reinforced with glass filaments

Polyester reinforced with glass filaments is mainly used as a protective supporting material in oil transformers. Polyester film provides resistance to breakdown, and the introduction of glass filament increases the breaking load. Such tapes are suitable for cable winding, insulation basic, external protection and insulation leaded wires.

Polyester tapes reinforced with glass filaments
Insulation class F 155°C
Series	Backing	Adhesive	Backing thickness, mm	Total thickness, mm	Color	Adhesion to steel, N/25mm	Tensile strength, N/25mm	Elongation, %	Dielectric strength (VDE 0303)	Read more
4238	polyester film/ glass filaments	AT	0.165	0.190	Clear	12.00	1642.00	5	6000
51597	polyester film/ glass filaments	AT	0.138	0.165	Clear	11.00	1095.00	5	5000

Tapes on the base of glass cloth

The advantages of such a basis are plasticity and flexibility, heat resistance, tensile strength and chemical resistance. Tapes on the base of glass cloth are suitable for all types of insulation.

Tapes on the base of glass cloth
Insulation class F 155°C
Series	Backing	Adhesive	Backing thickness, mm	Total thickness, mm	Color	Adhesion to steel, N/25mm	Tensile strength, N/25mm	Elongation, %	Dielectric strength (VDE 0303)	Read more
4616	glass cloth	RT	0.127	0.178	White/Black	13.70	767.00	3	3000
4617	glass cloth	AT	0.127	0.178	White	11.00	875.00	3	3000
Insulation class C 200°C
4618	glass cloth	SiT	0.127	0.178	White	12.30	810.00	3	3000

Additional information

Materials in stock

To find out presence and price of the interested tape and to place your order, you can in our online-stock.

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