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System diagnostyczny do bezinwazyjnej oceny stanu klatki wirnika silników indukcyjnych

Sułowicz Maciej, Duda Arkadiusz, Zielonka Jakub, Tulicki Jarosław, Cholewa Dariusz, Czechowski Mirosław

Maszyny Elektryczne : zeszyty problemowe

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2022

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Nr 1 (127)

229--236

PL

Ocena stanu klatki silników indukcyjnych jest ciągle aktualnym problemem diagnostyki stanu tych maszyn. Na rynku zasadniczo nie ma urządzeń, które mogły by w sposób kompleksowy automatycznie diagnozować uszkodzenia klatek silników zarówno podczas stanu ustalonego w oparciu o metodę MCSA jak i podczas rozruchu wykorzystując analizę przetworzonego przebiegu prądu rozruchowego. Na podstawie wieloletnich doświadczeń, autorów artykułu, w prowadzeniu badań stanu klatek wirnika dla wielu maszyn w różnych gałęziach przemysłu, opracowano urządzenie pomiarowe i specjalistyczne oprogramowanie pozwalające diagnozować rożne typy silników indukcyjnych klatkowych podczas rozruchu jak i stanu ustalonego. W artykule przedstawiono sposób pomiaru sygnału diagnostycznego, którym jest prąd stojan. Odwołano się do wiarygodności pomiarów diagnostycznych. Przedstawiono funkcjonalność oprogramowania do pomiarów diagnostycznych i analiz podczas stanu ustalonego i rozruchu. Przedstawiono wyniki wybranych pomiarów diagnostycznych, formy prezentacji wyników oceny stanu oraz przedstawiono przykłady zastosowania opracowanego systemu w badaniach przemysłowych w różnych gałęziach przemysłu.

EN

The assessment of the cage condition of induction motors is still a current problem in diagnosing the condition of these machines. There are basically no devices on the market that could comprehensively and automatically diagnose damage to motor frames, both during the steady state based on the MCSA method and during start-up using the analysis of the processed inrush current waveform. Based on many years of experience of the authors of the article, in conducting research on the condition of rotor cages for many machines in various industries, a measuring device and specialized software were developed to diagnose various types of squirrelcage induction motors during start-up and in the steady state. The article presents the method of measuring the diagnostic signal, which is the stator current. The reliability of the diagnostic measurements was referred to. The functionality of the software for diagnostic measurements and analyzes during steady state and start-up is presented. The results of selected diagnostic measurements, forms of presentation of the results of condition assessment and examples of the application of the developed system in industrial research in various branches of industry are presented.

2

How the axial flux of an induction motor can be used?

Petryna Janusz

Science, Technology and Innovation

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2019

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Vol. 5, no. 2

34--43

EN

The article contains the results of research within the project to apply unipolar (axial) flux to obtain diagnostic signals carrying the information of: electrical asymmetries of machinery (inter-turn stator short-circuits, cage damages); rotational speed of the rotor and load torque. Inter-turn stator short-circuits can be detected both at starting process time (when they appear most often), as well as in steady states. Detection of rotor cage defects in steady states has a character of a comparative study, and over time, as the defects develop. For standard drives that are powered from the network and work in open systems, by measuring the voltage following a unipolar flux, it is possible to make measurement and recording of motor speed, which usually is almost never provided under industrial conditions. The study shows that a simple in its construction, cheap coil can be a very useful diagnostic tool. The measurements were carried out at the laboratory and motor workplace in the power plant, while in the test station, during the loading, characteristics illustrating the dependence of the torque on the axial flux and on the rotational speed were obtained. A way of using a single measurement to estimate the torque has been proposed. The method is relatively simple to implement and allows for a fully non-invasive determination of the load torque.

3

Wpływ uszkodzeń klatki wirnika na wartość napięć i prądów wałowych w silnikach indukcyjnych

Zientek P., Niestrój R.

Maszyny Elektryczne : zeszyty problemowe

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2010

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Nr 86

157-161

EN

The paper presents initial results of laboratory investigations. These results emphasize the intensification of the phenomena connected with bearing currents flow at different rotor cage damages. In the section 3 is presented the influence of rotor cage damages on the shaft voltage value. The subject of these studies was a low power induction motor (fig. 3), taking into consideration easiness and low costs of necessary modernization of it. On the figure 4 is presented the diagram of the shaft voltage and current measurement system. The measurements results are presented on the figures 10, 11, 12. Conclusions drawn from laboratory researches are presented in chapter 4.

4

Wpływ uszkodzeń klatki wirnika na wartość napięć wałowych w silnikach indukcyjnych

Drak B., Zientek P., Niestrój R., Boboń A.

Maszyny Elektryczne : zeszyty problemowe

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2009

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Nr 84

117-120

EN

The paper presents initial results of laboratory investigations. These results emphasize the intensification of the phenomena connected with bearing currents flow at different rotor cage damages. In the section 2 is presented the influence of rotor cage damages on the shaft voltage value. The subject of these studies was a low power induction motor (fig. 2), taking into consideration easiness and low costs of necessary modernization of it. On the figure 3 is presented the diagram of the shaft voltage and current measurement system. The measurements results are presented on the figures 5, 6. Conclusions drawn from laboratory researches are presented in chapter 3.

5

Wpływ uszkodzeń klatki wirnika i nasycenia rdzenia na wartość napięć wałowych w silnikach indukcyjnych

Zientek P., Niestrój R.

Maszyny Elektryczne : zeszyty problemowe

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2008

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Nr 80

239-244

EN

The paper presents initial results of laboratory investigations. These results emphasize the intensification of the phenomena connected with bearing currents flow at different rotor cage damages. In the section 2 on the figure 5 are presented results of investigations connected with inducing of the third harmonic of the motor EMF. In the section 3 is presented the influence of rotor cage damages on the shaft voltage value. The subject of these studies was a low power induction motor (fig. 6), taking into consideration easiness and low costs of necessary modernization of it. On the figure 7 is presented the diagram of the shaft voltage and current measurement system. The measurements results are presented on the figure 8. Conclusions drawn from laboratory researches are presented in chapter 4.

6

O uszkodzeniach klatek wirnika

Bernatt M., Rut R., Mróz J.

Maszyny Elektryczne : zeszyty problemowe

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2008

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Nr 79

7-12

EN

Rotor cage failures are not regarded as the main cause of the induction motors breakdowns. An induction motor with broken squirrel cage bars can still be exploited, consecutive starts may be executed. At durability tests carried out by Komel Centre some years ago on a prototype 800 kW induction motor, it was stated, that even if 80% of the rotor bars were broken, the motor started fairy successfully and could be loaded. But any rotor cage failure (e.g. single bar or end ring fracture) causes electromagnetic asymmetry of the motor; main technical features of the motor are heavily deteriorated. Sound power level and vibration level become higher, efficiency factor lower, temperature rise of the stator winding may by higher. Starting (locked rotor) and breakdown torque is lower. In the paper special laboratory tests of a standard, 4 kW, 1500 RMP, 3 phase motor with aluminium rotor cast are presented. The tests were carried out on symmetric ("healthy") squirrel cage and on the cage with one, three and six broken bars. Several examples of large AC motors with damaged rotors and a reliable method for rotor squirrel cage diagnostics are presented.