Sector zero excitation tap switch

The utility model relates to a fan-shaped off-circuit tap-changer which is essentially consisting of an insulation base, a fix contact set, a moving contact set, a gear shaft and a gear rack. The insulation base is designed as fan-shape, the fix contact is fixed in the groove of the insulation base by screws, a gear rack is arranged at the position corresponding to the fix contact, one end of the pillar passes through the waist form hole of the gear rack and is fixed by the inset-nut on the insulation base, the other end passes through a pressure plate and is fixed by a nut; the moving contact on the gear rack contacts with the three corresponding fix contacts, the gear rack meshes with the gear shaft, one end of the gear shaft passes through the fan-shaped insulation base and the flange plate and its end is riveted with the handle. The utility model's characters are 1. It is easy to install on the side wall of the box-type transformer so as to make its fix contact connect with the tap lead of the transformer simply and reliably. 2. The original space can be fully used and no reserved space is needed for the installation of the tap-changer so as to decrease the transformer's costs. The utility model completely overcomes the shortcomings existing in the prior off-circuit tap-changer used in the box-type transformer.