In this paper, the charging characteristics of high-Tc superconducting (HTS) field coils are analyzed experimentally to verify the efficiency of using HTS contactless rotary excitation devices (CREDs). The HTS CRED is composed of eight HTS rotor strands, which are connected in series with HTS load coils, and eight neodymium permanent magnets (N50). The magnetic field of N50 is approximately 0.14 T when the air gap between the HTS rotor strand and N50 is 8 mm. In order to verify the proper charging method, two types of experiments are performed. In the first experiment, the HTS loads are connected in series and are charged by eight HTS rotor strands of the HTS CRED. In the second, the HTS loads are located along the same axis, and each coil is charged by four HTS rotor strands of the HTS CRED. In these experiments, the currents flowing through the HTS loads are measured for rotor speeds ranging from 50 to 300 r/min.
Bibliographical noteFunding Information:
Manuscript received August 29, 2017; accepted January 13, 2018. Date of publication January 23, 2018; date of current version February 1, 2018. This work was supported by the National Research Foundation of Korea funded by the Korea government (MSIP), Republic of Korea, under Grants 2017R1A2B3012208 and 2016R1A2B4007324. (Corresponding author: Jeyull Lee.) J. Lee, H. Jeon, S. Han, and T. K. Ko are with the Department of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, South Korea.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering