On the history of developing genera

On the history of developing generators of larger
capacity to meet increasing power demand, the purpose
is for developing SCGs. (Higher efficiency, smaller size
and so on are of course purposes.) On the history,
generators of larger capacity have been designed and
manufactured by larger electric loading AC, which has
some limitation. Then increasing magnetic loading was
mandatory, which made us use superconducting magnet
for field winding. On the background mentioned above,
in about 1970, develop of SCGs started in the USA,
Germany, USSR (Russia), France, Japan and so on. At
the beginning, SCGs of rotating armature type was developed
because it was very difficult to transfer Liq.He
from stationary part to rotating part. The first SCG of
rotating field type of 45 kV A was manufactured by MIT
in 1969, where Liq.He could not be transferred in the
rotating condition