A non-intrusive method for estimating motor efficiency using vibration signature analysis

Abstract

An accurate method of estimating the efficiency of in-service motors is needed in order to determine the performance of installed motors without disrupting the motor driven process.. In this paper, the motor efficiency is estimated using a non-intrusive implementation of the compensated slip method. The motor speed is accurately estimated using motor vibration signature analysis. A few other efficiency estimation techniques are implemented and their performance is compared to the proposed method. It was found that the non-intrusive compensated slip method produced relatively accurate results without having an adverse impact on the availability of the motor under test. This method provides an attractive alternative to highly intrusive techniques that offer similar accuracy.

An improved motor replacement strategy using non-intrusive motor efficiency estimation

“…A non-intrusive compensated slip method that uses the motor speed estimation based on vibration signature analysis is proposed for determining the motor operating point [7].…”

“…The rotor speed can be determined by analysing the frequency components of the motor vibration signal. This is achieved by applying a Fast Fourier Transform (FFT) to the sampled motor vibration signal [7]. The speed estimation technique is used together with the Ontario Hydro compensated slip method.…”

“…The efficiency estimation technique presented in [7] can be used to determine the motor efficiency curve at each point of the motor load cycle. The efficiency curve of the energy-efficiency replacement motor can be requested from the motor manufacturer.…”

“…(6) The annual savings that will be achieved by reducing the maximum demand are determined using (7). (7) where is the power saving in kW and is the demand charge. The total annual saving, is given by (8).…”

A PLL-Based Online Estimation of Induction Motor Consumption Without Electrical Measurement

“…Electrical power can then be calculated from motor models. Traditionally, the signal spectrum is obtained using an FFT algorithm [1][2][3] or Time-frequency methods when signals are non-stationnary [4]. As it will be seen in the following, the motor models require a high precision on the frequency measurement.…”