BS EN 60404-15:2012+A1:2017

This part of IEC60404 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 Table1. The methods given are for applied magnetic field strengths of between 5kA/m and 100kA/m. Table1 Relative magnetic permeability ranges for the methods described Measurement method Relative magnetic permeability range Solenoid 1,003 to 2 Magnetic moment 1,003 to 1,2 Magnetic balance 1,003 to 5 Permeability meter 1,003 to 2 NOTE1 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. NOTE2 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 effects. See AnnexA for more information on correcting for self-demagnetization.