Outdoor disconnectors switches type ONIII are designed for application in the outdoor switchboards of high voltage. Disconnectors are used for metallic isolation os systems by creating in open position a visible isolating distance.They are appropriate for switching small currents or currents when no significant change in voltage occurs across the terminals and can be operated in many types of high voltage switchgears. For earthing and short-circuiting disconnected plant section, each disconnector pole can be equipped with one or two earthing switches.

Catalog and project materials:
• Catalogue sheet in pdf format
• Dimensional draft in AutoCad format
• Dimensional draft of bracket construction in AutoCad format

  - Adobe Acrobat Reader

CONSTRUCTION:
Disconnectors are single-pole units, two column, with rotary moving contacts in horizontal plane. The main circuit is constituted of two co-operating knife - sets (left and right), which are fixed to the post insulators. The current flows from the terminal to a set of two U-sections of the main circuit, through a set of self-springy contacts. A set of self-springy contacts is assembled of adynamical springy contacts (contact pressure is increased during flow of short circuit current). The main central contact is assembled of two sets of self-springy contacts and a self-adjusting central contact. In closed position of the disconnector central contact is enclosed from two sides by self-springy contacts. In open position the knives are almost parallel one to another, forming an insulating distance. The base of the disconnector is made as a rigid welded frame of steel shapes. The base is furnished with two bearing housings with ball-bearings and rotary supports, on which the post insulators are mounted. Ball-bearings are greased-for life. Flat levers set on ends of rotary supports, together with pull-rods and a crankshaft, constitute a gear ensuring contrariwise rotation of the insulators of about 90°. The earthing knife of a disconnector during closing operation first swangs out to vertical position and next, inserts axially into the tulip like earthing contact on the main circuit. The bars of tulip-like contact are self-springing and shaped so as to assure a considerable increase of contact pressure due to the electrodynamics action of short-circuit currents. Flexible copper connecting lead connects the lower end of the knife with the base. The coupling mechanism is intended for constituting three single-pole disconnectors into a three - pole group. It transmits the rotation of one crankshaft to the crankshafts of the remaining single-pole disconnectors, constituting the poles of the group. The operating mechanism may be coupled to any of the single-pole disconnector (as requested by the client). Rotary motion of the shaft coupling the operating mechanism with the disconnector causes rotation of the disconnectors crankshaft at 192°. The pull-rod drives insulators, which rotate contrariwise at 90°, together with the main circuit knives, left and right. The earthing switch is driven by a pull-rod attached to a crankshaft. Appropriate lever gear cross the dead points, preventing the disconnector and earthing switch against inadvertent opening or closing, due to some electrodynamical or external forces (short-circuit currents, storms). In case of three-pole groups, the external forces acting on the main circuit, or on the earthing switch of any of single-pole disconnector of the group, are not transferred on the coupling mechanism, or on the output shaft of operating mechanism. Reaching closed and open position by individual single-pole disconnectors and their earthing switches is practically simultaneous, thus a three-pole group operates as a single unit.

CHARACTERISTIC FEATURES (PDF):