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Transformer Foil Strip

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Aluminium Strip for Transformer Winding
Flat Aluminium Strip / Aluminium Flat Strip in China
    Transformer strip is used in transformers for electrical engineering and in power distribution, which means in power plants and substations, in local distribution networks, in wind power, industrial plant and the power adaptors belonging to electronic devices.

Transformer Aluminium Foil Specification
Product name
Transformer Aluminium Foil
Henan Signi Aluminium Co,Ltd

This Specification specifies aluminium foil used as conductors for transformers
 ( hereinafter abbreviated as “foil” ).
2.Applicable Dimensions
The applicable dimension of foil shall conform to table 1.

Table 1
  Unit : mm
Thickness 0.3 to 2.4
Width 25 to 1250

3.Outline of the quality
3.1 The chemical composition of shall conform to table 2.

Table 2
   Unit : weight %
Si Fe Cu Mn Mg Cr Zn Ti Others Al
Individual Total
- max.
- min.
3.2 Mechanical properties and electric conductivity shall conform to Table 3.

Table 3
Thickness Tensile strength
Bending 180 buckling inside radius Electric conductivity
% at 20°C
Over 0.3 to 0.5   Less than 75 25min.   Close contact   62.5min
Over 0.5 to 0.8   Less than 75 30min.   Close contact   62.5min.
Over 0.8 to 1.3   Less than 75 35min.   Close contact   62.5min.
Over 1.3 to 2.0   Less than 75 35min.   Close contact   62.5min.
Over 2.0 to 2.4   Less than 75 35min.   Close contact   62.5min.

3.3 Dimensions shall conform to Table 4 which indicates dimensional tolerances.
   Table 4
Unit : mm
Thickness Tolerance in thickness Tolerance in width
Guaranteed value - 25 to 300 Over 300
to 600
Over 600
to 1250
Over 0.3 to 0.5 ±0.02   ±0.3 ±0.5 ±1.0
Over 0.5 to 0.8 ±0.03   ±0.3 ±0.5 ±1.0
Over 0.8 to 1.3 ±0.04   ±0.3 ±0.5 ±1.0
Over 1.3 to 2.0 ±0.04   ±0.3 ±0.5 ±1.0
Over 2.0 to 2.4 ±0.05   ±0.3 ±0.5 ±1.0
3.4 Inside diameter, outside diameter and unit weight shall conform to Table 5.

Inside diameter Outside diameter Remarks
150mm, 305mm 1200mm Paper core.    Special demand could be talk.
Note:The classification of Table 5 may be disregarded if particularly specified otherwise.Or Depeneding on customer’s requirements.

3.5 Coil’s deformation shall conform to Table 6.
Table 6.

- -
Deformation of inside diameter (Max. - Min.) < 10
3.6 Coil winding
Coil winding shall be as follows.

3.7 Interphase insulation foil
 The interphase insulation foil for aluminum foil protection is unnecessary.
4. External Appearance, ETC.
(1) The surfaces of foil shall be clean and smooth and shall be free of noxious defects for use such
as wrinkles, distortion and flaws. The foil edge in particular shall be free of flaws.
(2) The foil shall be free of attachment of substances which are noxious for use such as oil, grease,
soapy water and metal powder.
(3) The edge of foil shall be in accordance with following conditions.
Precision slit :
all sizes (schematic)
max. burr size 3% of thickness or max. 0.05mm.

The edge quality shall comply to table below.

Table 7
  Sectional shapes of sheet edge
5. Tests and Inspections
1) Inspection of external appearance
Defects in the quality specified in item 4 shall not be found as a result of visual inspection and inspection by hand feeling.
2) Chemical test
The test result shall conform to GB/T3190.
3) Tensile strength and Elongation test
The test result shall conform to GB/T228.
4) Electric conductivity test
The test result shall conform to Appendix 1.
5) Dimensional inspection
Measurement of thickness and width shall be taken using micrometer, slide calipers, tape measure, straight-edge, etc.
6. Packaging
Packaging shall be made that the center axis of roll shall be made on the horizontal direction

  Both eye to wall and eye to Sky packing are available for us.
Moisture proof packaging shall be made for delivery for convenience of carriage and handling and
also in order not to allow occurrence of uncoiling, rusting, damage, etc. at the occasions of storage,
carriage, warehousing, etc.
7. Test Record
Inspection and tests described item 5 shall be carried out on each.
Aluminium foil size and shall be carried out on each delivery.
Test record shall include the result of the tests and inspection and shall be submitted with the invoice.
8. Marking
The following matters shall be marked by a suitable method at easy-to-see places of each foil
and package.
1) Type and grade
2) Dimensions and quality  ( at the front and the opposite side )
3) Month of production and serial number
4) Manufacturer’s name
5) Gross Wt.
6) Net Wt.
9.Slitting Machine

Machine name Slitting thickness
HLSF1400 Thickness ≦1.0mm
1850 Thickness >1.0mm

HLSF1400                                           1850

Method for measurement of electric conductivity
The test specimen shall be of a length of 300 mm or longer as a rule. The electric resistance shall be
measured in a constant temperature chamber of 15-20°C.

…in case of mean sectional area method

…in case of superposing method
Where; Rt: Electric resistance of specimen at t°C (Ω)
1 : Length of electric resistance measuring section (m)
m : Weight of specimen (g)
2 : Length of specimen (m)
a : Mean sectional area of specimen (mm2)
A : 0.017241
C : 0.04655 (assuming the specific gravity as 2.7)
α20 : Constant mass temperature coefficient at 20°C

Transformers have hearts – hearts made of coils of wound copper. The principle is always the same, whether in large-scale transformers, power transformers, oil distribution or cast resin transformers.
Typical areas of use
Here are some of the areas in which transformer strip is used:
Power and electrical engineering
Industrial systems
Wind farms


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