What is an Electrical Isolator?

The Isolator is one type of mechanical switch used to isolate a fraction of the electrical circuit. Isolator switches are to open electrical circuits in the no-load condition. While current flows through the line, we should not open the electrical circuits. Generally, these are employed on both ends of the circuit breaker; thus, we can do the circuit breaker repair quickly without any risk. 

Electrical Isolator separates any electrical component from the system while the system is offline/ online. The Isolator doesn’t include any system for avoiding arching throughout disconnection. An electrical isolator switch disconnects a power transformer in an electrical substation once it is in a no-load situation; otherwise, a tiny load is there. In full load conditions, isolators don’t operate.

How does an Isolator work?

An electric isolator working principle is simple as it operates in different ways like manually operated, semi-automatic, and fully automatic. These sometimes act as switches, which are known as electrical isolator switches. Depending on the necessity, we can open or close this switch. Nevertheless, sometimes, these are arranged in a fixed position permanently to maintain isolation, like transformers in electrical transmission lines or grid stations.

An electrical isolator switch is one device used to isolate a specific circuit by preventing and maintaining flowing currents. Electrical appliances such as kitchen tools, power grids, etc., have these switches. Isolator switches have various types: single-pole, double-pole, 3-pole, 4-pole, fused, and battery isolator switches.

What are different types of Isolators?

We can classify electrical isolators by the requirement of the system, which includes the following: Single-break Type Isolator, Double-break Type Isolator, and Pantograph Type Isolator.

  • Single Break Isolators:

For single break isolators, arm contact is separated into two elements. The first arm contact holds male connection, and the second arm contact keeps female contact. The fixed post insulator rotation upon which the arm contacts makes the arm contact shift.

The rotation of post isolators stacks in reverse to shut the Isolator by preventing arm contact. Post insulators counter-rotation stacks will open the arm contact, and an isolator rotates into an off condition. 

  • Double Break Isolators:

This type of Isolator includes three loads of post insulators. The middle insulator holds a flat male or tubular contact turned straight by a middle post insulator’s spin. The center post insulator’s rotation can be made by a lever method at the bottom-end of the post insulator. This also relates to manual operation (operating handle) or motorized operation motor (using motor) of the Isolator via a mechanical knot rod.

  • Pantograph Isolator:

The pantograph isolator allows current switchgear installation, which requires the least space. This type of insulator includes a post insulator as well as an operating insulator.

Isolators can be classified into three types by the power system location: bus side, line side, and transfer bus side isolator:
  • Bus Side Isolator: a kind of Isolator that connects by the primary bus.
  • Line Side Isolator: it stays bound by an inline feeder side.
  • Transfer Bus Side Isolator remains bound by the primary bus of a transformer.

How to operate isolators?

We can operate an electrical isolator by the two following operational methods: opening and closing.

  • Opening Operation of Electrical Isolator:

We begin by open the major circuit breaker and divide the load from a system with an isolator opening. After that, we close the earth switch. It is possible to turn an earth switch into an interlock system with an isolator. Only when we open the isolators, the earth switch can be closed.

  • Closing Operation of Electrical Isolator:

First, we detach the earth switch, shut the Isolator, and then shut the circuit breaker.

What are the applications of Isolators?

  • The applications of isolators are various, including as follows:

  • Use in high voltage devices such as transformers.

  • Stop accidental usage by isolators, protected with a lock or a locking system on the external. 

  • When an error occurs in a substation, the Isolator cuts out a substation portion.

There are various fields of application of isolators: automotive, optoelectronics, medical, and household appliances.


Who manufactures isolators?

Isolators are essential electronic parts, so many reputable manufacturers make these components, including Texas Instruments, Analog Devices Inc., Rochester Electronics, Infineon Technology, Maxim Integrated, ON Semiconductor, etc.


Where to buy isolators?

Apart from the manufacturers, customers in the electronic sector can source isolators online by electronic components websites such as Findchips, Octopart, or Digipart, which allow users to compare and connect to manufacturers and distributors. BD Electronics is also a distributor that has been the partner with these websites. We provide our customers with all types of electronic components, including isolators.

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