Isolator may be a operated by hand mechanical switch that separates a section of the electric power. Isolators area unit accustomed open a circuit beneath no load. Its main purpose is to isolate one portion of the circuit from the opposite and isn’t meant to be opened whereas current is flowing within the line. Isolators area unit usually used on each ends of the breaker so as that repair or replacement of electrical fuse will be dodged and danger.
Types of Electrical Isolators
There are differing kinds of isolators on the market relying upon system demand like
- Double Break Isolator
- Single Break Isolator
- Pantograph type Isolator.
Depending upon the position in the power system, the isolators can be categorized as
- Bus side isolator – the isolator is directly connected with main bus
- Line side isolator – the isolator is situated at line side of any feeder
- Transfer bus side isolator – the isolator is directly connected with transfer bus.
Constructional Features of Double Break Isolators
These have 3 stacks of post insulators as shown within the figure. The central post stuff carries a hollow or flat male contact which may be revolved horizontally with a rotation of central post stuff.
This rod sort contact is additionally referred to as moving contact. the feminine sort contacts square measure
fastened on the highest of the opposite post stuffs that fitted at either side of the central post insulator. the feminine contacts square measure typically within the variety of elastic device figure contacts. The move movement of male contact causes to return itself into feminine contacts and isolators becomes closed. The rotation of male contact within the wrong way build to that out from feminine contacts and isolators becomes open.
Rotation of the central post insulator is completed by a driving lever mechanism at the bottom of the post insulator, and it’s connected to in operation handle (in case of hand operation) or motor (in case of motorized operation) of the isolator through a mechanical rod.
Constructional features of Single Break Isolators
The contact arm is split into 2 components one carries male contact and alternative carries feminine contact. The tangency moves thanks to rotation of the post nonconductor upon that the contact arms
are fitted. Rotation of each post insulators stacks in opposite to every alternative causes to shut the isolator by closing the contact arm Counter rotation of each post insulators stacks open the contact arm and isolator becomes in off condition. This motorized type of this sort of isolators is usually used, however associate emergency hand driven mechanism is additionally provided.
Constructional features of Pantograph type Isolators
The pantograph mechanism is put in on the support material and transfers the move¬ment of the rotating material to the arms of the mechanical device disconnector. The mechanism is housed in associate atomic number 13 enclosure, protective it again¬st pollution and ice. The springs that compensate the load of the mechanical device arms are put in during this housing. every mechanical device is supplied with four atomic number 13 arms to make sure a rigid construc¬tion with a awfully high contact rating.
The main contacts square measure product of copper, with a silver plated surface. The counter contact could be a horizontal copper bar, silver-plated, that must be connected to the busbar system.
A bus isolator is an off load switch that connects the road breaker and therefore the bus. It sits between breaker and bus.
A line isolator is an off load switch that connects the road breaker and therefore the line. It sits between breaker and current electrical device.
Transfer bus side isolator.