A diagnostic center for remote state estimation of induction motors

A fast development of the computer based diagnostic and data acquisition systems as well as ever falling cost of various types of sensors and converters, together with the possibility of data transmission via various telecommunication systems, create an opportunity to build and to implement the diagnostic systems for the induction motors. This paper presents a concept of a Diagnostic Center for diagnosis of induction motors. We propose a distributed measuring system so called "telemeasuring" system which supporting diagnostic services located in a specialized Diagnostic Center. As for data transmission, the Internet and the LAN networks are used as inexpensive links, as it is more cost efficient to provide a remote the maintenance of the diagnostic service. The concept of the diagnostic system takes into consideration, on one hand the database of diagnostic patterns, on the other hand the database of archival measurements taken while using the machine. The functioning blocks of the diagnostic inference subsystem (the main element of Diagnostic Center) are presented. The realization of the Measuring Server WWW (the main element of distributed measuring system located in Diagnostic Center) is also described in detail in this article

A distributed system of diagnostics signal acquisition for induction motors

In this paper, the realization of a distributed measuring system is presented. The so called Tele-Measuring System (TMS) is developed at our University. As for data transmission via TMS, the Internet and the Ethernet networks are used as inexpensive reliable links. The measuring process requires installation of suitable sensors or actuators. In our case, we used the Hall effect converters (LEM), which convert the measured values of currents to voltage. The implementation of the LEM sensors in the Ethernet network requires an installation of a new smart device (data collector) that has an A/D converter, microcontroller with data flash and a LAN controller with embedded WEB server in one small package. The data collectors equipped in Ethernet 10Base-T adapters with RJ-45 connectors allow to build local measuring networks in star topology up to 100m distance between measuring object and nearest hub or switch. This board makes many measuring applications imaginable. Think of a diagnostic that can be easily controlled using either special front-end software and comfortable Internet browser from anywhere around the World. The detailed TMS elements design is described in this article

Main inductances of induction motor for diagnostically specialized mathematical models

In the paper modeling of main inductances for mathematical models of induction motors is applied to study the effects caused by a rotor eccentricity and saturation effects. All three possible types of eccentricity: static, dynamic and mixed are modeled. The most important parameters describing rotor eccentricity include self and mutual inductances of the windings. The structural changes of the permeance function as a result of eccentricity appearance and the Fourier spectra of inductances in occurrence of saturation for each case are determined in the paper. The presented algorithm can be used for the diagnostically specialized models of induction motors

Realization of chosen functions for diagnostic network system of electrical drives

The fault detection and diagnosis in drive systems has practical great significance. Modern noninvasive diagnostics of induction cage motors usually bases on Fourier spectra of stator currents. Creation of individual diagnostic system for one specific motor is very expensive. This problem can be transfer to specialized Diagnostic Center. The aim of this center is to provide detection and diagnosis damage in motors as such outsourcing service. For realization diagnostic applications, Diagnostic Center provide for a specialized data-base. Information can be analyzed in this center by expert systems and faults can be detected before they lead to a partial or total failure of the machine. It requires of installation suitable equipments for remount control measurements and data acquisition in industrial plant. That system offers advantages like: reduction of costs measure and data collection, immediate data delivery and independence from distance to measured object. In this paper, we propose a distributed tele-measuring system supporting Diagnostic Center. As for data transmission, Internet and industrial Ethernet net is used as inexpensive link

Application of fuzzy inference system for diagnostic cage induction motor

This paper presents a diagnostic conclusion block, based on a fuzzy logie approach. It proposes implementation of a decision making, algorithm based diagnostic system, in order to achieve an uninterrupted work cycle of the squirrel cage motor drives. The diagnostic conclusion interface has been designed on the basis of the diagnostic data, obtained from the analysis of the phase currents spectra and symmetrical components of the currents spectra. Indicators for the diagnostic evaluation have been selected on the basis of the solutions of the mathematical model of the motor, which takes into consideration the eccentricity of the rotor. The principle of work of the diagnostic conclusion block designed to evaluate the state of the rotor has been presented for a selected motor. Artificial intelligence, including fuzzy logie, applied in the conclusion systems increases the system's ability to derive characteristic relationships and correlations, which are not recognizable by traditional diagnostic methods, thus giving a higher possibility of forming a correct diagnosis. This is especially important in situations, when the correct interpretation of the measurement data and the diagnostic indicators requires knowledge, coming from the engineering experience

Acquisition system of diagnostic signals for state estimation cage induction motor

This paper presents a procedure of acquisition of diagnostic signals, needed for a comprehensive diagnostics of squirrel cage motors. The is data obtained from a Data Acquisition Card (DAQ), measuring transducers and a database. The procedure allows the measurements of the required quantities and data transfer to the server via the LAN Network or the Internet. Basic diagnostic signals required to evaluate the condition of the squirrel cage motor are three phase currents and phase voltages feeding the stator of the machine, measured at the same instant. The system delivers data needed to the comprehensive diagnostic of the squirrel cage motors, especially the ones used to detect faults which are difficult to recognize without simultaneous measurements of motor currents and control of a stator voltage symmetry. Simultaneous measurement of the three currents and the three voltages is necessary for the diagnostic methods, based on the analysis of the specific features of the motor currents component's spectrum described by the authors. This paper contains examples of the diagnostic signal analysis collected and stored with the use of the developed data acquisition system

Foraging activity of bats in Scots pine stands in different growth stages

Scots pine (Pinus sylvestris L.) is economically the most important tree species in Polish forestry. Congeneric pine stands have a quite low level of biodiversity, and logging with clear sites may even cause their further decline. It is very important to discover the influence of clear−cuttings in managed pine stands on different groups of organisms. One of them are bats which play an important role in forest biotopes as a regulator of insect pests. The aim of this paper is to compare the foraging activity of bats in pine stands of different stages of growth. The study was carried out in three complexes of pine forests in western Poland: Drawska Forest, Notecka Forest and Dolnośląskie Forests. Four types of growth phases were studied: clear−cut sites (Z), young plantations in the age 2−5 years (U), 41−60−years−old stands (III) and mature stands in the age over 80 years (V). The study of the foraging bat activity was conducted with broadband ultrasound detectors Pettersson D−1000X within 3 hours after sunset in summer periods of 2013 and 2014. The recordings were analyzed with BatSound software. Total 19 180 bat passes were recorded on all 120 sampling plots. 11 bat species: Nyctalus noctula, Pipistrellus pipistrellus, Eptesicus serotinus, P. nathusii, Myotis myotis, P. pygmaeus, M. nattereri, Barbastella barbastellus, N. leisleri, E. nilssonii and Vespertilio murinus and four groups of species: NEV (Nyctalus, Eptesicus, Vespertilio), MSP (Myotis), PSP (Pipistrellus), and PLE (Plecotus) were recognized (tab. 1). The dominant was common noctule N. noctula (71.5%). The highest foraging activity of bats was recorded in open areas: clear sites and plantations (fig. 1), next in mature stands and middle−aged stands. The obtained results suggest that bats can adapt to a mosaic of habitats created by clear−cutting harvesting system in managed pine forests