The high voltage disconnector is a device for the safety of a plant or an electrical circuit. It has the task of opening a circuit or a line, so physically and visibly perceptible, separating two points electrically connected to each other so there is no more metallic continuity between them. A disconnector can be associated to a switch, but this one has a limit in terms of maximum current opening.
The worst condition is represented by short circuit, in which the component is traversed by short-circuit current (Icc). While the disconnector opening up is guaranteed if and only the crossing current is less than short circuit, the disconnector does not have this limit, being characterized by the capacity to resist “closed” to the passage of short-circuit current.
The disconnector task is to disconnect safely the voltage from the plant, in order to enable people to access the system itself for performing work, involving contact with live parts or activity close to the plant.
Today there are different types of disconnector: manually controlled or by motor. The disconnector are different regarding of their arm movement (Horizontal disconnector, vertical, central break, double-side break, arm pantograph vertical break knee type, earthing switches), but also regards the tyep of the movement (manually from an operator, by a motor).
Independently from break disconnector type, the mechanism box positioned beneath each break disconnector, contains the geared motor for the machine members handling and the control panels. There must be the manual handling of the break disconnector in case of failure of the geared motor with an handling time fixed at 15 seconds by the main reference Standards.
Motovario offers a range of product that can be selected according to the design and the type of the disconnector, which best suits on the application. The reducer selected is a worm gear reducer, NRV design, size 63 up to 90.
Motovario has developed a particularly design of the worm shaft, modifing also the oil seal; it is used a grease lubrification and a particularly linkage on the worm shaft and worm wheel due to the high speed on the input shaft.
Usully is used a 4 poles motos, but solutions are possible event with 6 and 8 poles motors in a power range between 0,22 and 0,55 kW. The manually movement, instead, is ensured by a special handle that thanks to the design of the worm shaft can be directly connected to it, so as able to actuate the gearbox without the electric motor.