1 Scope
This standard specifies the test methods of AC magnetic properties of materials other than electrical steel and soft ferrite in the frequency range of 20Hz to 20kHz. Materials involved in this standard include: special alloys listed in IEC 60404-8-6; pressing, sintering and metal injection molding components listed in IEC 60404-8-9; and soft magnetic composite materials for castings.
The purpose of this standard is to clarify the general rules and technical details of testing the magnetic properties of soft magnetic materials by the use of ring specimens. For powdery materials, ring specimens shall be made by proper extrusion.
The DC magnetic properties of soft magnetic materials shall be measured according to the ring specimen measurement method in IEC 60404-4. The measurement of magnetic characteristics of soft magnetic elements shall be carried out according to IEC 62044-3: 2000.
Generally, testing shall be carried out at the ambient temperature of (23±5)°C, and the ring specimens shall be demagnetized before testing. Testing may be carried out in other temperature ranges upon negotiation by both parties.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments (excluding correction of error) to, or revisions of, any of these publications do not apply. However, parties to agreements based on this national standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
GB/T 3655 Methods of measurement of the magnetic properties of electrical steel sheet and strip by means of an Epstein frame (GB/T 3655—2008, IEC 60404-2: 1996, Methods of measurement of the magnetic properties of electrical steel sheet and strip by means of an Epstein frame, IDT)
IEC 60404-4 Soft magnetic materials — Part 4: Measurement methods of DC magnetic properties of soft magnetic materials
IEC 60404-8-6 Magnetic materials — Part 8-6: Technical requirements of individual materials Soft magnetic metal materials
IEC 60404-8-9 Magnetic materials — Part 8-9: Technical requirements of individual materials — Sintered soft magnetic materials
IEC 62044-3: 2000 Measurement method of magnetic cores made of soft magnetic materials — Part 3: Magnetic properties under high magnetization field
3 General
The measurement is carried out under the closed magnetic circuit of ring specimens with one or two windings.
3.1 Test specimen
Ring specimens with rectangular cross section made in the following different ways shall be adopted:
a) a clock spring-shaped iron core formed by winding a thin strip or wire;
b) ring specimen laminations formed by punching, laser cutting or photochemical etching;
c) powder pressing and sintering, metal injection molding or casting.
For powder materials, if the ring specimens are made by metal injection molding or pressing (and possibly heating), these methods shall be carried out according to the suggestions of the material manufacturer to achieve the best magnetic properties of the powder materials.
For all types of test specimens, burrs and sharp edges shall be removed before heat treatment. For soft magnetic alloys, the ring specimens shall be put in a ring box which can be divided into two parts; and for test specimens without insulation layer, appropriate insulation measures shall be taken when stacking them. For high permeability materials, it is best to put the ring specimens in a ring box which can be divided into two parts. The size of the box shall closely match with the test specimens to avoid stress in the material.
The ratio of the outer diameter to the inner diameter of the test specimen size shall be no greater than 1.4, preferably less than 1.25.
For the belt materials with thickness less than 0.15mm, a strip with width of 10mm shall be taken along the rolling direction, coated with an insulating layer and wound into a ring specimen.
For solid and powder pressed materials, the dimensions of the test specimen, that is, the outer diameter, inner diameter and height of the ring specimen, shall be measured by an appropriate and calibrated measuring tool, and the accuracy of the measuring tool shall be ±0.02mm or better. The relevant dimensions shall be measured at different positions of the test specimen, and the average value shall be calculated. The cross-sectional area of the test specimen shall be calculated from Equation (1):
Foreword iii
1 Scope
2 Normative references
3 General
3.1 Test specimen
3.2 Winding
4 Temperature measurement
5 Measurement of permeability and magnetization curve by V-A method
6 Measure the specific total loss with power meter
7 Measuring magnetic properties by the use of digital impedance bridge
8 Measuring magnetic properties by digital method
9 Reproducibility
10 Test report
Annex A (Informative) Comparison between this standard and IEC 60404-6: 2003 in clause number
Annex B (Informative) Technical differences and their causes between this standard and IEC 60404-6: 2003
Annex C (Informative) Requirements for windings and apparatuses used in order to minimize additional losses
Annex D (Informative) Digital control method of sine waveform
Annex E (Informative) Modified Hay's bridge measurement method
