• Progress in Superconductivity and Cryogenics
• /
• v.14 no.1
• /
• pp.30-33
• /
• 2012

A double pancake winding method is widely used to make the superconducting magnet, using high temperature superconductor (HTS) tape. In the double pancake winding method, the joints with contact resistances between double pancake coils are inevitably needed. The electrical joule heating on the contacts causes refrigerant loss during operation. And a space outside the winding, for splices and mechanical support, is more than that for its layer-wound equivalent. In this paper, a double pancake winding method in order to reduce the number of the joints was proposed. Both of the double pancake coils using the conventional winding method and the proposed winding method have been fabricated and tested to make the solution technically feasible in the double pancake winding method. Especially, critical-current tests of the fabricated double pancake coils were conducted in order to show the same performance and confirm contact resistances between double pancake coils.

• Progress in Superconductivity and Cryogenics
• /
• v.12 no.4
• /
• pp.31-35
• /
• 2010

In superconducting magnet applications, winding methods of the superconducting magnet can be classified into a layer winding and a pancake winding. The superconducting magnet using high temperature superconductor (HTS) with rectangular shape is generally fabricated using the pancake winding method. On the other hand, low temperature superconducting (LTS) magnet may be wound by either a pancake winding or a layer winding. Compared with the layer winding, the pancake winding method has a merit of easy replacement of a damaged pancake module, but it also has a demerit of requirement of splicing between each double pancake modules. In this paper, we investigated characteristics of the layer and pancake winding methods using HTS. Six samples were wound out of BSCCO and Coated Conductors (CCs) by two winding methods and their characteristics were experimentally observed.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2002.02a
• /
• pp.297-299
• /
• 2002

To wind a HTS (High Temperature Superconductor) tape conductor on a bobbin, double pancake winding technique is widely used to reduce number of splicing contacts between conductor pieces. However, this makes some Ic (critical current) degradation on kink points which is unavoidable. This paper describes the two ways of winding; usual double pancake and soldered double pancake. Characteristics of the two windings are measured and compared.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.263-265
• /
• 2003

A winding machine to fabricate the double pancake coils was manufactured. A race-track type double pancake coil using high temperature superconductor (HTS) tape was prepared and I-V and I-H characteristic curves were obtained at the atmosphere of liquid nitrogen. The winding method to make the double pancake coil and its properties is discussed.

• Progress in Superconductivity and Cryogenics
• /
• v.12 no.1
• /
• pp.37-41
• /
• 2010

To limit fault current in a power system, superconducting fault current limiters (SFCLs) using high temperature superconducting (HTS) coils have been developed by many research groups so far. Non-inductive winding of HTS coils used for SFCLs can be classified into solenoid winding and pancake winding. Each of winding is expected to have different quench and recovery characteristics because the structure of solenoid winding differs from pancake winding's. Therefore it is important to the SFCLs application to investigate characteristics of each winding. In this paper, we deal with quench and recovery characteristics of four kinds of winding : solenoid winding, pancake winding without spacers, and with spacers of 2 and 4 mm thickness. In order to obtain quench and recovery parameters of coils, short circuit tests were performed in liquid nitrogen.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.3
• /
• pp.384-389
• /
• 2008

The cental magnetic field of an HTS magnet consisting of pancake windings can be increased if the magnet is excited by multiple power sources. Multiple power sources enable all pancake windings to conduct their critical currents. The HTS magnet consisting of pancake windings was excited by separate power sources in this paper. Critical currents of each pancake winding were determined by using optimization technique. Fabrication of the BSCCO magnet consisting of 10 pancake windings is described and test results of the BSCCO magnet are given. Central magnetic field and perpendicular magnetic field of the magnet excited by multiple power sources were compared with those of the magnet excited by a single power source.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.11
• /
• pp.1970-1975
• /
• 2008

Critical current of the superconducting machines is limited by the magnetic field. When the magnetic field is not uniform, it is difficult to estimate the magnetic field and the critical current. This paper proposed a method for the estimation of the magnetic field and the critical current of the HTS pancake windings which can be used to generate the high field magnet. A parameter which was needed to calculate the critical current of a BSCCO magnet with 10 pancake windings was obtained by the experiment. Test which was carried out by using single pancake winding and magnet consisting of 10 pancake windings shows the proposed method can be an effective method for the estimation of the critical current of pancake windings.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.9
• /
• pp.572-577
• /
• 2000

This paper describes the test results of a single phase 3kVA high temperature superconducting power transformer. The tapes are made with Bi-2223 and have silver alloy as the matrix. Four double pancake windings are used. Among them two double pancake windings are connected in series for high voltage winding and the others are connected in parallel for low voltage winding. The rated voltage and current of primary winding and secondary winding are 220/110V. 13.7/27.3A. Fundamental characteristics are obtained through short circuit and no load test. The over load capability and characteristics are investigated.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.1
• /
• pp.27-31
• /
• 2000

This paper presents the performance evaluation of an HTS transformer. Numerical calculation by finite element method was used to evaluate the performance. BSCCO-2223 HTS tapes and double pancake winding were adopted in this design. Four double pancake windings were used in total. Among them two windings were connected in series for high voltage winding and two windings are connected in parallel for low voltage winding. Propertied of various type of the winding arrangement were examined. Characteristics of the transformer during the transient which was caused by sudden short were simulated. The current limiting effect, temperature rise and resistance growth of the superconducting winding were shown.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.3
• /
• pp.101-106
• /
• 2003

The high temperature superconductor transformers gain interests from the industries. This paper described construction and test results of 10㎸A HTS transformer Three phase transformer with double pancake windings were constructed. To reduce the leakage magnetic field, secondary coil were placed between the two primary coils. BSCCO-2223 wire. silicon sheet steel core and FRP cryostats were used to construct the transformer. Three coils were stacked in one cryostat. Two double pancake coils were connected in series for the primary coil and one double pancake coil was used for the secondary coil. Total number of turns of the primary winding and the secondary winding were 112turns and 98urns, respectively, The rated voltages of each winding were 440/220V. The rated currents of each winding were 13.1/26.2A. After the tests of basic properties of the three phase HTS transformer using no-load test, short-circuit test and full-load test, continuous operation of 100 hours with pure resistive load has been carried out. Test results proved over-load capability and reliability of the HTS transformer.