Since 1989 development of a practical superconducting generator has been ca
rried out in Japan. The authors have developed a rotor having a superconduc
ting field winding and a stator having an air gap winding composed of a dou
ble transposed copper coil. A series of tests were completed at the end of
last year. The output of 78.7MW was recorded which is the highest value yet
obtained world wide. Test results of the shop test in 1996 and the site te
st in 1997 and analysis are described.