Tap changer for power transformer - having insulation tube for housing vacuum switches and current limiting resistors

摘要

A cylindrical insulation housing (73) contains the vacuum switches (V1-V9), current limiting resistors (66-68), and mechanical gearing (71) for the tap changer. Switches (V1-V9) and resistors (66-68) are mounted on an insulation plate (78) located inside the housing and perpendicular to its longitudinal axis. The moving contacts of the vacuum switches are linked to the mechanical gearing (71) by rods (80) made of insulating material. The housing contains the relevant components for all the phases of the tap changer. They are arranged circumferentially round the support plate (78). Barriers (91) may be provided to separate the phases. The gearing is at earth potential and linked to an external operating mechanism (5, 6, 92). The electrical selector contacts for the taps are contained in a separate assembly (60-65) below the housing(73) containing the vacuum switches.