Abstract: A field control apparatus for a generator having a field winding comprises a terminal voltage control unit for controlling a field current of the generator in accordance with a difference between a terminal voltage signal of the generator and a reference voltage signal, which control unit has at least one of a line drop compensation function, an under-excitation limitation function, an over-excitation limitation function, a power factor regulation function, an armature winding over-current compensation function and a cross-current compensation function. The field control apparatus includes a detector as a common signal source for detecting active power and reactive power components at an output terminal of the generator and means responsive to the output of the detector for performing scalar operation in accordance with a function of the added compensation/control function described above.

Abstract: Nut which is separated into segments so that the segments can be expanded or contracted being guided at a tapered hole formed in the nut segments, characterized in that a tapered hole has an inlet port at a narrower end and an insertion hole at a broader end so that a bolt to be fastened can penetrated therethrough; nut segments have guide pins at their back which are always urged by a spring toward the narrower side of the tapered hole, and an operation ring is rotatably fitted to the outer periphery of the main body, and the operation ring is provided with a cam part which, when the operation ring is turned, moves the guide pins toward the broader side of the tapered hole against the spring to keep the positions of the nut segments, or releases the guide pins so that the nut segments are restored to the narrower side of the tapered hole by the force of the spring.