Design and implementation of a DSP-based personal instrumentation system for testing performances of electrical motors

The successful application of digital signal processing (DSP) techniques to measure dynamic torque-speed characteristics of electrical motors is presented. An algorithm based on the fast Fourier transform (FFT) and finite impulse response (FIR) filtering techniques is introduced. The dynamic measurement algorithm is implemented on a PC system, consisting of an Apple IIe computer with a data acquisition and a load control unit. This system provides an accurate estimation of motor torque by performing the filter function in the frequency domain instead of in the time domain on a sampled speed waveform. The algorithm for measuring dynamic torque for motor start-up is derived. The implementation of the automatic measurement system with an Apple IIe is described. The experimental results have confirmed the validity of the proposed systems