• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.8
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• pp.373-380
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• 2003

This paper consists of a study in post-assembly magnetization of LSPM (Line Start Permanent Magnet Motor). Recently, LSPM is noted as an alternative to the induction motor because it offers a very high efficiency and unity power factor, And it is necessary for permanent magnets to be magnetized by means of post-assembly magnetization in LSPMS because of the manufacturing cost involved. The manufacturing process is also simpler in post-assembly magnetization than in pre-assembly magnetization. Generally, permanent magnet motors are magnetized by their own stator coil or by magnetizing fixtures. However, the permanent magnet in a LSPM is scarcely magnetized by using them because of the eddy current of the rotor bar. Hence, it is necessary to design a magnetizing fixture that overcomes this problem. In this paper, the author analyses the post-assembly magnetization of a LSPM and proposes a method for designing the magnetizing fixture. The method that the author proposes is to make the number of coil turns greater in order to reduce the effect of the eddy current of the rotor bars.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1610-1613
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• 2016

An analytical method for harmonic estimation of magnetization currents has been developed. The method is based on the results of the waveforms qualitative analysis. The calculation and the experimental results are compared. A good matching is observed.

• Progress in Superconductivity and Cryogenics
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• v.21 no.1
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• pp.1-5
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• 2019

The pulsed field magnetization of the short-circuited soldered double pancake coil made of stabilized commercial high-Tc superconductor (HTS) tape is experimentally studied. The evolution of the shielding current induced by the pulsed field and the trapped field after the pulsed magnetization was measured at 77 K. It is shown that the trapped field in the coil is close to the value reached in the field cooling process and reduces weakly at 5-fold increasing of pulsed field amplitude. The current relaxation at t~2 ms after the pulse is defined by the current sharing between the tape's copper coating and the $YBa_2Cu_3O_{7-d}$ layer. In the intermediate time scale (1 s < t < 100 s) the flux creep in HTS layer dominates. At t > 100 s the current's relaxation is defined by the resistance of soldered joint between tapes.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.34-38
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• 2005

Multi-stacked HTS tapes are needed to conduct large current in the power application. In this paper, magnetization losses of the multi-stacked YBCO coated conductor and the BSCCO tape have been measured and compared. Magnetization losses of single tape, 2-stacked, 3-stacked and 4-stacked HTS tapes have been presented in this paper. Multi-stacked tapes have been fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various angle of external magnetic field to consider the anisotropic characteristics of HTS tapes. Test results show that loss density per unit volume decreased for both YBCO coated conductors and BSCCO tapes when the stacking number of tapes is increased. The magnetization losses of YBCO CC are larger than those of BSCCO tapes when the external magnetic field is increased.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.57-60
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• 2007

Superconducting electric power devices need to stack HTS wires to increase the current carrying capacity. Uniform multi-stacked wires(UMS) which were made of the same HTS wires have been used. This paper shows the magnetization loss of hybrid multi-stacked(HMS) wire made of BSCCO wires and YBCO wires. Five HMS wires, YB(YBCO-BSCCO), YYBB. YBYB, YBBY and BYYB, were made and tested. Magnetization losses of each UMS wire were compared with corresponding HMS wire. Test results show that magnetization losses per unit length of HMS wire are between the corresponding UMS BSCCO wire and HMS YBCO wire below critical magnetic field. Above the critical magnetic field, magnetization losses of HMS wires are larger than that of corresponding both VMS wires.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.2
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• pp.83-88
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• 2006

AC loss is one of the main research area in AC power application using high temperature superconductor(HTS), such as HTS transformer, HTS current limiter and HTS cable, because it is closely related to efficiency, economic estimation and design of power device. A lot of research for various arrangements of HTS tapes have been performed to increase a capacity of transport current because single HTS tape can not satisfy the demanded current capacity in HTS power application. In this paper, we studied magnetization loss by different several arrangements of BSCCO tapes such as Edge-to-Edge type, Face-to-Face type and Matrix type through numerical analysis by 2D-FEM and measurement. As a result, we got the result that the magnetization loss of Face-to-Face type arrangements was lower than those of other arrangement types under the conditions of the same stacking number. We think that the result was due to shield effect by demagnetization of adjacent HTS tapes which are located face to face.

• Journal of the Korean Magnetics Society
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• v.14 no.4
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• pp.115-119
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• 2004

We measured in-plane 2 dimensional magnetization vector using two pick-up coil sets and investigate the relationship between magnetization vector and anisotropic magnetoresistance. We can determine magnetization vector by measuring magnetic moment in x and y direction simultaneously. As the uniaxial magnetic anisotropy of permalloy film increases, magnetoresistance approaches the expectation which is calculated from the angle between current vector and magnetization vector. Magnetoresistance ratio is linearly proportional to the y moment magnitude which is parallel to the current direction.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.13-16
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• 2005

Multi-stacked HTS tapes are needed to conduct large current in the power application. In this paper magnetization losses of the multi-stacked YBCO coated conductor and the BSCCO tape have been measured and compared. Magnetization losses of single tape, 2-stacked, 3-stacked and 4-stacked HTS tapes have been presented in this paper. Multi-stacked tapes have been fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various stacked of external magnetic field to consider the anisotropic characteristics of HTS tapes. Test results show that loss density per unit volume decreased for both YBCO coated conductors and BSCCO tapes when the stacking number of tapes is increased. As the external magnetic field decreased, the ratio of decrement has risen because the full penetration magnetic field(Bp) of the multi-stacked tape is larger than that of the single tape.

• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.15-19
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• 2009

Recently, it is proposed to make striations on the YBCO coated conductor and to transpose each other as one of the solutions to decrease the perpendicular magnetization loss. For large power application using HTS, the stacked conductor packing the YBCO coated conductors should be used because single conductor is limited in flowing of demanded large current. In this paper, we research the affect of the striation and continuously transposed stacking geometry on the magnetization loss in perpendicularly exposed magnetic field. Several short samples having different number of striation and continuously transposed stack are prepared and tested in perpendicularly exposed magnetic field for the magnetization loss characteristics. The magnetization loss of striated sample was lower than sample without striation. The reduction effect on magnetization loss by the striation is obviously appeared in higher field and lower number of stack and decreased as increasing the transposed stacking number. Also, the reduction effect by transposed stack is obviously appeared in lower field at lower number of striation and isn't appeared at higher striation number and higher magnetic field.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.10.1-10.1
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• 2007