Optimization of the parameters of the current transducer of block protection of electric motors

Abstract

We determined the parameters of a current and voltage inductive transducer with a magnetic core made of a ferromagnetic material. The inductive transducer is used as a part of the block multifunctional protection of three-phase asynchronous electric motors. An equivalent circuit of a passive inductive current transducer is given. We determined the main relationships connecting the output voltage of the transducer with the measured current. Modeling of parameters was performed to expand the ranges of measured currents at a fixed frequency and in a wide frequency range. We examined the operating modes of the transducer at an idle speed, with a short circuit. The mathematical model takes into account the characteristics of the magnetic circuit, the possibility of its saturation, the higher harmonic components of the sensor output signal.