Disconnect contact assembly

Claim 1

A disconnect contact assembly comprising: a tubular insulator having a bottom and an open end; a grounded shutter plate provided at the open end of said tubular insulator for closing said open end; a stationary arm fixed on said bottom and having a contact end protruding into said cylindrical insulator along the axial direction; an electric field moderating ring surrounded in a radially-spaced relationship by said tubular insulator and surrounding and electrically connected to said stationary arm and protruding for a predetermined distance from said contact end of said stationary arm toward said grounded shutter plate but which does not extend to the level of the open end of said tubular insulator to have a sufficient clearance of insulation from said grounded shutter plate; and a movable arm reciprocally movable along said axial direction between one position at which the movable arm comes into contact with said contact end of said stationary arm while said grounded shutter plate is open and another position at which the movable arm is out of said cylindrical insulator while said grounded shutter plate is being closed wherein said stationary arm and movable arm are surrounded in a radially-spaced relationship by said electric field moderating ring.