Motor current signature analysis

This paper shows how the speed of an induction motor (IM) can be extracted from the motor currents of an induction motor with a Labview implementation of motor current signature analysis (MCSA). The implementation is first applied to an IM driven by the 60 Hz mains. The estimation system consists of data acquisition, demodulation, and FFT spectrum analyses. The estimation is then extended to PWM inverter-fed IM drives. For PWM drives, the presence of stator current harmonics and a variable fundamental frequency demands filtering and a more powerful demodulation technique. The above estimation algorithms are implemented in Labview for Windows.