PURPOSE: To prevent an influence of a grounding failure of a coil from extending, by a method wherein a toroidal feild coil which is excited by direct current through devices such as AC circuit breakers, a rectifier transformer and a rectifier is grounded by a resistance whose value is minimum 5 times and maximum 50 times of that of the coil when the maximum current is applied.
CONSTITUTION: A toroidal source circuit which is composes a torus type nuclear fusion equipment is composed of an AC source 10, AC circuit breakers 11 and rectifier transformer to which the breakes 11 are connected. A rectifier 13, a source side sound toroidal field coil inductance 15, a source side sound toroidal field coil resistance 16, an earth side sound toroidal field coil inductance 17 and an earth side sound toroidal field coil resistance 18 are provided and a junction of the resistance 16 and the inductance 17 is grounded by a line 22. Then an end of the redtifier transformer is grounded by a resistance 14 whose value is prescribed between 5 and 50 times of that of the coil.
NISHIO SATOSHI
TAKIZAWA TERUHIRO
SHIZUOKA YOSHIHIDE
HITACHI LTD
HITACHI SERVICE ENG