Operation diagnosis for centrifugal pumps using stator current-based indicators

Abstract

Motor current signature analysis (MCSA) used in the diagnosis of centrifugal pumps has become a hot topic due to its non-intrusive and cost-effective nature. Yet, traditional current-based diagnosis methods show limitations as massive computation and power frequency interference. Moreover, most of them focus on the fault detection, fewer discuss the applications in operation evaluation. Therefore in this article, the hydro-mechanical-electric coupling effect that exists in the induction motor-centrifugal pump system is analyzed systematically. On this foundation, novel indicators that can reflect the harmonic distortion and noise proportion of stator current signals, and further indicate the hydraulic stability and operation status are proposed. Theoretical and experimental analysis support this paper, and results have demonstrated that our proposed indicators can indicate the operation change, identify the optimal operation region, and reflect the development of cavitation for centrifugal pumps. These indicators have the advantages of easy calculation and identification, therefore can be conveniently compared with accepted standards and enable immediate remedial actions to be implemented to ensure the stable operation.

Off-Design Operation and Cavitation Detection in Centrifugal Pumps Using Vibration and Motor Stator Current Analyses

“…Rotor rotational speed frequency and blade passing frequency are inherent in centrifugal pumps, which indicate the torque oscillation characteristics, given by f r =2(1-s)f e /P n (24) f BPF =k b f r (25) where s, fe, Pn, and kb are the slip, the power frequency, the pole-pair number, and the blade number.…”

“…Time-frequency characteristics extracted from the current signals using HHT were selected to indicate the cavitation severity in a centrifugal pump. In [20] Fault diagnosis for centrifugal pumps based on vibration and current signals has been well investigated but not to the same extent as off-design operation detection [24]. Centrifugal pumps operating in off-design conditions would cause additional hydraulic torque disturbance forces, and the internal flow status of centrifugal pumps would become unstable, with excessive turbulent disturbance generated.…”

Investigation on the Vibration Induced by Rotary Shaft Seal Condition in a Centrifugal Pump

“…Pumping devices constitute the most prevalent type of mechanical equipment in industry that convert mechanical energy into fluid energy 1 .…”