accredited testing laboratory

accredited testing laboratory

The accredited testing laboratory is subject to regular surveillance audits by the Czech Institute for Accreditation, which strictly controls both the systemic and professional aspects of the laboratory and evaluates whether it applies established, approved procedures and meets the strict binding requirements of the standard. The Czech Institute for Accreditation is a member of international organisations (EA, ILAC, IAF) and has signed multilateral international agreements EA (European level) and ILAC, IAF (global level) on the mutual recognition of accreditation results. The results of the accredited testing laboratory of PZK BRNO a.s. are accepted by all signatories to the above agreements. Due to the laboratory’s unique instrumentation, we subcontract tests from the Czech Metrology Institute (CMI).

certificates

measurement of magnetic properties of permanent magnets using a hysteresisgraph pursuant to EN 60404-5

Measurement of magnetic properties of permanent magnets using a hysteresisgraph based on standards ČSN EN 60404-5 ed. 2 and ASTM A977/A977M-07 (equivalent to ČSN EN 60404-5 in the USA). The measurements on the hysteresisgraph record the second quadrant of the hysteresis loop, which characterises all magnetic materials. All the main parameters of permanent magnets can be read from the record. The same parameters are also listed in the catalogues of permanent magnet manufacturers. These parameters include:

• remanent induction Br – the residual magnetic induction in the magnet at a zero intensity of the magnetic field after the magnet has been saturated is determined in the graph by an intersection point of the hysteresis loop and coordinate axis B and equals the magnetic polarisation in that point.
• HcB coercivity – the magnetic field intensity at which the zero magnetic induction was reached after the magnet has been saturated is determined in the graph by an intersection point of the B(H) hysteresis loop and coordinate axis H in the 2nd quadrant.
• HcJ coercivity – the magnetic field intensity in the magnet at which the zero magnetic polarisation was reached after the magnet has been saturated is determined in the graph by an intersection point of the J(H) hysteresis loop and coordinate axis H in the 2nd quadrant.
• BHmax energy product – the maximum value of BH product along the demagnetisation curve;; the maximum product equals double the energy density (volume unit energy) of the magnetic field in the magnet and corresponds to the largest rectangle under the BH curve in the graph.

measurement of magnetic dipole moment under EN 60404-14

The magnetic moment is primarily the property of elementary particles. As the magnetised magnet is an arranged material structure, these moments add up together, resulting in a magnetic dipole moment of the magnet, which is then measured by means of a fluxmeter and Helmholtz coils. This measurement gives a value relative to the material and volume of the magnet. The magnetic dipole moment can only be measured for two-pole magnetised permanent magnets. It is appropriate where variations between larger sets of identical samples are monitored, e.g., between different deliveries or production batches, and where it is not cost-effective or is impossible to make hysteresis measurements due to the size or shape of the magnets.

For more detailed information on the performed tests, see the Annex to the Accreditation Certificate or ask for it.