Fault Diagnosis in a Centrifugal Pump Using Active Magnetic Bearings

Abstract

The number of rotors running in active magnetic bearings (AMBs) has increased over the last few years. These systems offer a great variety of advantages compared to conventional systems. The aim of this article is to use the AMBs together with a developed built-in software for identification, fault detection, and diagnosis in a centrifugal pump. A single-stage pump representing the turbomachines is investigated. During full operation of the pump, the AMBs are used as actuators to generate defined motions respectively forces as well as very precise sensor elements for the contactless measurement of the responding displacements and forces. In the linear case, meaning small motions around an operating point, it is possible to derive compliance frequency response functions from the acquired data. Based on these functions, a model-based fault detection and diagnosis is developed which facilitates the detection of faults compared to state-of-the-art diagnostic tools which are only based on the measurement of the systems outputs, i.e., displacements. In this article, the different steps of the modelbased diagnosis, which are modeling, generation of significant features, respectively symptoms, fault detection, and the diagnosis procedure itself are presented and in particular, it is shown how an exemplary fault is detected and identified.

Model-based fatigue crack identification in rotors integrated with active magnetic bearings

“…With this simplification Equation (8) is modified as When the AMB is incorporated in the sustentation of the rotor with a crack, the AMB force can be put in the right-hand side of Equation (7) with an appropriate sign. If the AMB is used as an external noncontact exciter, as reported in a multitude of crack-related literature (Aenis et al., 2002; Nordmann and Aenis, 2004; Quinn et al., 2005; Litak et al., 2009; Sawicki et al., 2009; Friswell et al., 2010), the AMB forcing appears in the right-hand side of Equation (7) with a positive sign. Since in this work the AMB is used as an additional support, its nature and purpose is to minimize the vibration displacement: the AMB forcing appears in the right-hand side of Equation (7) with a negative sign.…”

HTGR Measurements and Instrumentation Systems

“…Fault-tolerant active magnetic bearing control design remains an active development area 88 as does active magnetic bearing-based fault detection in centrifugal pumps. 89 Fault-tolerant control can be combined with system diagnostics to improve overall circulator reliability. For example, the circulator active magnetic bearing control would typically be powered by three-phase power supplies.…”

Centrifugal Pump Impeller Crack Detection Using Vibration Analysis

“…Non -dimensional time domain features (i.e kurtosis, Skewness, etc.) have been used as input to ANN for centrifugal pump fault diagnosis (cavitation, impeller damage and unbalance), [5] Rainer Nordmann and Martin Aenis [7] developed built-in software for identification, rotor crack and wear detection, and diagnosis in a centrifugal pump based on the measurement of the systems outputs, i.e., displacements.…”