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...tance. High speed motors at high-frequency sinusoidal current waveform, whichscan make the effective winding resistance very high and for that reason copper losses aresincreasing when frequency grows =-=[1, 2]-=-. The winding resistance of high speed motor is a result of both skin and proximity effects [2-5]. The main phenomenon that leads to ac losses issthe skin effect which is the tendency for high-frequen...

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...ion as compared to dc operation. The ratio of the equivalent ac resistance or copper loss to the ideal dc value Rac /Rdc (Pac /Pdc) is a commonly usedsfigure of merit to assess high frequency effects =-=[8]-=-.s,2 dc ac ac rmsiS l R RP ⋅= ρs(4)swhere irms is the RMS current, ρ is the resistivity of medium, l is the length of copper wire andsS is the cross section of conductor.sThe copper power losses (Pdc,...

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... For instance, one of the common methods for reducing ac resistance is the Litz wire,sand that method greatly reduces the cross-sectional area of the conductor and drasticallysincreases dc resistance =-=[6, 7]-=-. Additionally the big open slot can cause significant losses insconductors, even at a small amount of ac current. Using a powdered core with no gap willssubstantially reduce proximity effects and the...

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.... The temperature was monitoredsat ac current and an operation frequency of 50 Hz. The temperature can rise faster and highersduring the time when the winding operates in very high range of frequency =-=[13]-=-. Also, increasing current in the coil leads to enhanced temperatures in the strands. The curve in Figure 12bsindicates that the distribution of power loss (eddy-currents) was not uniform in the coppe...

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...and the smaller the dc copper losses are. Rectangular conductors are predominantly woundswith their higher facing the stator pole. Moreover, rectangular conductors have a tendency tosdecrease ac loss =-=[16]-=-. To demonstrate the phenomena of loss reduction, two different arrangements of winding are investigated in respect to the ac resistance and copper losses at highsfrequency operation. Figure 6 shows a...

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...The ferrite core size determines the large opening slotshence the copper losses in strands placed near the slot opening region are suspected to produceshuge amount of eddy-current due to flux leakage =-=[4, 10]-=-. Winding losses can be reduced bysproperly arranged conductors and designed shape of teeth including the size of slot opening.sAdditionally, copper losses are dependent on electrical parameters such ...

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... For instance, one of the common methods for reducing ac resistance is the Litz wire,sand that method greatly reduces the cross-sectional area of the conductor and drasticallysincreases dc resistance =-=[6, 7]-=-. Additionally the big open slot can cause significant losses insconductors, even at a small amount of ac current. Using a powdered core with no gap willssubstantially reduce proximity effects and the...

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...The ferrite core size determines the large opening slotshence the copper losses in strands placed near the slot opening region are suspected to produceshuge amount of eddy-current due to flux leakage =-=[4, 10]-=-. Winding losses can be reduced bysproperly arranged conductors and designed shape of teeth including the size of slot opening.sAdditionally, copper losses are dependent on electrical parameters such ...

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...erature e.g. a method based on the finite integrationstechnique for the discretization, which gives an equivalent thermal model allowing the evaluation of transient temperature evolutions in the slot =-=[11, 12]-=-. The temperature was monitoredsat ac current and an operation frequency of 50 Hz. The temperature can rise faster and highersduring the time when the winding operates in very high range of frequency ...

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...erature e.g. a method based on the finite integrationstechnique for the discretization, which gives an equivalent thermal model allowing the evaluation of transient temperature evolutions in the slot =-=[11, 12]-=-. The temperature was monitoredsat ac current and an operation frequency of 50 Hz. The temperature can rise faster and highersduring the time when the winding operates in very high range of frequency ...

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...e to back iron where flux leakage crossing the slot window is smaller [4]. Furthermore, end-winding may produce significant proximity losses and thus influence eddy-currentsscirculation in conductors =-=[17]-=-. Figure 7b shows copper losses in the slot (PCu_active-length) and insthe end-winding region (PCu_end-winding) separately. It is easily noticed the end-winding generates lower loss than losses in the...