Thermographic Measurement and Simulation of Power Losses Due to Interlaminar Contacts in Electrical Sheets

An Enhanced Analysis of Inter-Laminar Faults in Magnetic Cores With Grain Oriented Electrical Steels for Fault Diagnosis and Condition Monitoring: Theoretical Background and Experimental Verification

“…TSM (5) shows that at (𝐵 𝑚 , 𝐻 𝑏 ) where 𝑑𝐵 𝑑𝑡 ⁄ = 0, dynamic magnetic field 𝐻 𝑑𝑦𝑛 (𝑡) is vanished, and total magnetic field 𝐻(𝑡) is exclusively equal to the hysteresis field 𝐻 ℎ𝑦𝑠 (𝐵(𝑡)). Similar conclusion can be conducted from model (8) for a stack of laminations subjected to ILF. As a phenomenological result, ascending branch of the SHL can be constructed from the (𝐵 𝑚 , 𝐻 𝑏 ) datapoints, which is the first step to construct the SHL.…”

“…An example of core failure at the T-joint of a three-phase distribution transformer is shown in Fig 1. Following decades of research and development, all aspects and concepts of ILFs and their consequences on the magnetic cores are fully understood for the design and operation engineers [8][9][10]. Therefore, to prevent irreversible failures and breakdowns of the device, it is widely acknowledged that fault diagnosis of magnetic cores should be conducted at an early stage.…”

Internal Characterization of Magnetic Cores, Comparison to Finite Element Simulations: A Route for Dimensioning and Condition Monitoring

“…During the machining processes, mechanical stresses can considerably affect magnetic properties. Furthermore, undesirable edge burrs around the cut edges and punched holes can be created, which results in interlaminar faults (ILFs) and negatively affects magnetic core efficiency [10]- [14]. ILFs can also occur during an operation because of multiple reasons, such as the vibration of loose windings, arcing from winding failure, transportation, and installation.…”

“…For geometrical problems, current laminated magnetic core characterizations are limited to either global information (averaged through the cross-section) or surface observations [2], [14], [25]. Embedding any instrumentation system inside a laminated magnetic core was difficult.…”

An Experimental Approach for Condition Monitoring of Magnetic Cores With Grain-Oriented Electrical Steels

“…Quality of the magnetic cores are determined by electrical and magnetic properties of the magnetic materials, coating of the laminations which determine the inter-laminar resistance between the laminations, clamping pressure, manufacturing processes, etc. Key amongst these are manufacturing processes which have direct impacts on properties of the materials and hence normal operation of the magnetic cores and related devices [1][2][3][4][5][6][7].…”