Effects of Laser-Cutting and Spark Erosion Techniques and Heat Treatment on the Magnetic Properties of Grain-Oriented Transformer Steels

Güneş, Taylan

doi:10.1007/s10948-018-4639-2

Cited by 2 publications

(5 citation statements)

References 18 publications

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“…To minimize plastic deformations, using an electrical discharge method was implemented under controlled conditions to pierce the sample . For sheets with double holes at the corners of the sheets before the cutting (BC), search master coils (MCs) were located in the middles of the samples.…”

Section: Methodsmentioning

confidence: 99%

“…Similar studies about heat treatment as well as cooling processes indicate that heating/cooling rates for transformer steels are averagely convenient to desired properties . For measurements, magnetizing (driving) coil on the frame was fabricated as single‐sheet solenoid frame magnet, which had 620 turns with enameled copper wire measuring 0.8 mm in diameter . Flux closure is provided by an 8‐mm‐thick frame made of grain‐oriented transformer sheets in conventional orientation as shown in Figure .…”

Section: Methodsmentioning

confidence: 99%

“…To minimize plastic deformations, using an electrical discharge method was implemented under controlled conditions to pierce the sample. 5 For sheets with double holes at the corners of the sheets before the cutting (BC), search master coils (MCs) were located in the middles of the samples. For sheets with single sheared holes in their middles (AC1H), sense coils, which were used to pick up signals, were wound 50 mm away from the holes' eroded edges.…”

Section: Methodsmentioning

confidence: 99%

“…13 For measurements, magnetizing (driving) coil on the frame was fabricated as single-sheet solenoid frame magnet, 14 which had 620 turns with enameled copper wire measuring 0.8 mm in diameter. 5,12 Flux closure is provided by an 8-mm-thick frame made of grain-oriented transformer sheets in conventional orientation as shown in Figure 2. For B(H) loop measurements, a LabVIEW-based software package and connected devices, including a Kepco power supply, a Lakeshore fluxmeter, and a Hamag HM 450-MHz analogue oscilloscope, was used to control pick-up signals.…”

Section: Methodsmentioning

confidence: 99%

“…Drilling effects on conventional laminated transformer‐core materials were previously investigated by cutting Fe‐3%Si steel parallel to a rolling direction . Specifically, this was done to study how the physical properties of holes affect cores' magnetic properties.…”

Section: Introductionmentioning

confidence: 99%

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Numerical and experimental analyses of the deterioration in magnetic flux density distribution on perforated transformer core steels

Güneş

2018

Int J Numerical Modelling

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The holes in transformer core sheets are necessary for tailoring transformer‐core designs even though they cause more or less deterioration in the magnetic properties. With using spark erosion, specimens were pierced as a circle shape at certain locations and diameters to compare their effects to the magnetic properties by means of hysteresis curves, Magneto‐optical Kerr imaging, and finite element method. It was found that piercing the middles and corners of sheets at regular intervals dropped the sheets' relative permeabilities to ranges of 28% to 70%. Additionally, significant increments in power losses, from 0.8 to 2.54 W/kg at 50 Hz, depending on increases in hole diameters, were noted. These effects did not occur in a non‐pierced sample. Furthermore, considering all possible scenarios based on hole diameters and locations, laminated transformer‐core sheets were simulated to study distributions of flux lines, flux densities, and magnetic forces using 2‐dimensional static magnetic analyses. Holes in the sheets and the holes' proximities to each other were noted using magneto‐optical Kerr microscopies. Kerr images and diagrams of flux propagation from the simulation were individually compared to consider how the sheets flux distributions were influenced by varying the physical properties of the holes. The cases' effects on basic transformer cores were also investigated using 2‐dimensional static analyses.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%