Magnetic materials – Part 15: Methods for the determination of the relative magnetic permeability of feebly magnetic materials
|Publication Date:||1 December 2016|
|ICS Code (Magnetic materials):||29.030|
|ICS Code (Electricity. Magnetism. General aspects):||17.220.01|
This part of IEC 60404 specifies a solenoid method, a magnetic moment method, a magnetic balance method and a permeability meter method for the determination of the relative magnetic permeability of feebly magnetic materials (including austenitic stainless steel). The magnetic balance and permeability meter methods are both comparison methods calibrated using reference materials to determine the value of the relative magnetic permeability of the test specimen. The relative magnetic permeability range for each of these methods is shown in Table 1. The methods given are for applied magnetic field strengths of between 5 kA/m and 100 kA/m.
NOTE 1 The relative magnetic permeability range given for the magnetic balance method covers the inserts provided with a typical instrument. These can only be assessed at values for which calibrated reference materials exist.
NOTE 2 For a relative magnetic permeability larger than 2, a reference material cannot be calibrated using this written standard. A note of this is given in the test report explaining that the values measured using the magnetic balance are for indication only.
The solenoid method is the reference method. The magnetic moment method described is used mainly for the measurement of the relative magnetic permeability of mass standards.
Two comparator methods used by industry are described. These can be calibrated using reference materials for which the relative magnetic permeability has been determined using the reference method. When suitable, the magnetic moment method can also be used. The dimensions of the reference material need to be given careful consideration when determining the uncertainty in the calibration value due to self-demagnetization