Electrical Isolator- Types, Working & Its Applications

An electrical isolator is a switching device that isolates or protects a circuit. Mainly, these switches are used in the distribution of electrical power. However, there is much more to know about these switches. If you are interested to learn about them, continue reading this post. It will discuss what an isolator is, its working principle, types, applications, and several other details that you must know. 

What is Isolator in Electrical Engineering?

In simple words, an electrical isolator is a kind of mechanical switch that isolates a part of a particular circuit when required. Typically, these switching devices are utilized to open a circuit in no-load condition and not when the current is flowing through the circuit. In a circuit, electrical isolators are placed at both ends of a circuit breaker to make it safe and easier to repair the breaker. These switches never work in full-load conditions. 

With brief information about what an isolator is, move on to the following section of this blog that will introduce you to the working mechanism of electrical isolators. 

Working of Isolator

The working principle of an electrical isolator is quite easy to comprehend as it works using different methods like semi-automatic, fully automatic and manually operated. Sometimes, operators use the isolators as switches for the circuits. As a result, they are also known as electrical isolator switches. In such cases, the operators open and close them based on the necessity. However, they are mostly located at a fixed position in a circuit and offer isolation to the circuit, like transformers. 

Electrical isolators are unique devices that isolate a specific part of a circuit to prevent as well as maintain the flow of current. Usually, these devices are used in power grids and kitchen tools. 

Types of Isolators

Electrical isolators are classified into three categories based on the system’s requirements-

Double Break Type Isolators

The Double break type isolators have three loads of post insulators. Among these three, the middle insulator has a tubular contact or flat male that is turned straight through spinning the middle post insulator. At the bottom of the post insulator, a lever method is used for the middle post insulator’s rotation. 

Single Break Type Isolators

Another type of isolator is the Single break type, which has its arm contact broken into two components. One of these arm contacts is responsible for holding the male contact, and the other one for holding the female contact. A shift is observed in the arm contact due to the rotation of the post-insulator upon which they are fixed. This rotation of the post-insulator is reversed to each other, resulting in shutting the isolator by the arm contact. The counter rotation opens the isolator as well as the arm contact. In cases of emergency, these isolators can also be operated manually. 

Pantograph Type Isolators

The Pantograph type isolators require the least space in comparison to other types. Also, they are installed through current switchgear installation. These isolators possess a post and an operating insulator. 

Electrical isolators are divided into three more categories based on the power system location. These are- 

Bus Side Isolator

The first kind of isolator based on the power system location is the Bus side isolator, which is connected by the major bus. 

Line Side Isolator

The Line side isolators are connected in the circuit through a feeder inline side. 

Transfer Bus Side Isolator

Another type of isolator is the Transfer bus side isolator that stays connected in the circuit through a transformer’s major bus.

Applications of Isolators

In addition to types and working mechanisms, when learning about these switches, it is also crucial to learn about the various uses of isolators. Below are the most significant uses of these devices. 

• Isolators are widely used to protect against accidental usage. They have a locking system or lock on the external that prevents accidental usage. 
• These are commonly used in high-voltage devices like transformers. 
• Isolators are used to cut out a portion of a circuit in a substation when a fault occurs in it. 

Maintenance of Isolators

Being a mechanical device, faults are natural to occur in electrical isolators. However, if they receive proper maintenance, these faults can be minimized. Below are some maintenance tips that must be followed to ensure their smooth operation. 

• Electrical isolators must be kept clean. They must be clean from salt cement and acid fumes. 
• Isolators must be replaced with new ones as soon as a defect is observed to prevent the entire circuit.
• The arrangement of contact rods should always be appropriate. 
• The connections of isolators must be tight, and regular inspection must be done to ensure these connections are in place. 
• Once the isolator is closed, the earth switch must be closed to check the mechanical interlock of the isolators. 

Several other maintenance steps must be taken to ensure appropriate maintenance for the electrical isolators. However, one key point to remember here is that safety measures must be followed when maintaining isolators, and if you do not know much about them, always rely on a professional to help you with the maintenance. 

Read Also - DIFFERENCE BETWEEN CIRCUIT BREAKER AND ISOLATOR / DISCONNECTOR

In Conclusion

Isolators are widely used to separate a faulty section of an electrical circuit from a healthy one to prevent further damage and efficient repair. These switching devices play a crucial role in the overall operation of a circuit. As a result, it is essential to ensure they are of premium quality. If you are looking to buy any type of electrical isolator, the online store of Schneider Electric is just the place for you. 

Frequently Asked Questions 

Q1. What is an Electrical Isolator?

Ans: An electrical isolator is a switching device that isolates a particular part of a circuit that is faulty from the well-functioning one for its repair. 

Q2. What are the different types of Electrical Isolators?

Ans: Electrical isolators are of the following types-

• Double Break Type Isolators
• Single Break Type Isolators 
• Pantograph Type Isolators

Q3. What is electric isolation?

Ans: Electric isolation refers to separating a faulty part of a circuit from the healthy part to repair it. Electrical isolators are used for this isolation.