Soft-magnetic ring core measuring system with a decreased number of primary and secondary winding turns

A computerized measuring system of magnetic properties of soft-magnetic ring cores according to the IEC 4042 is presented. Special attention is paid to its robustness in order to assure the precise and fast measurement needed in the intensive magnetic component industry. To reduce the connection time of the specimen, the proposed test circuitry-in contrast to other well-known and applied solutions-uses a low number of primary and secondary turns. Such a solution increases demands that need to be fulfilled by a power supply generating the magnetizing current. This paper explains how a sinusoidal magnetic polarization of the core is maintained and introduces solutions to avoid a premagnetized magnetic core and power amplifier instability.