In an air circuit breaker, we use the air as an arc quenching medium. The air has several advantages over oil as an arc extinguishing medium. These are as follows: Air Circuit Breaker Working Principle In the air circuit breakers, we extinguish the arc by increasing its resistance. We lengthen the arc with the help […]
For the measurement of large currents and high voltages in AC circuits, specially constructed accurate ratio transformers are used in conjunction with low range AC instruments. These specially constructed transformers are known as instrument transformers. Types of Instrument Transformer There are two types of instrument transformer. These are: Potential Transformers (PTs) Current Transformers (CTs) These instrument
Hi friends, In this article, I am explaining the vacuum circuit breaker working principle and construction, and hoping you would like my article. The high vacuum has a high dielectric strength, and the current interruption in the high vacuum occurs at the first current zero. These two properties of high vacuum make the vacuum circuit
Hi friends, in this article, I am explaining the SF6 circuit breaker working principle and construction. This article will increase your knowledge; I hope so. In the oil circuit breakers, air circuit breakers and low oil circuit breakers, arc extinction take place slowly after the moment of contact separation. Hence, the arc is usually extinguished
Hi Friends, In this article, I am going to discuss the circuit breaker working principle and hope you will find it interesting and useful. Circuit breakers are mechanical devices designed to make and break the electrical circuits under normal and abnormal conditions. Automatic circuit breakers, which are generally used for the protection of electrical circuits,
As in the case of plain oil circuit breaker described earlier, the quantity of oil required reaches very high figures with the increase in system voltage. This vast quantity of oil increases the size of the breaker and maintenance problems. We know that the oil in the circuit breaker performs two functions. Firstly, it acts
In an oil circuit breaker or OCB, the separating contacts of the breaker are made to separate within an insulating oil because insulating oil has better insulating properties than air. Oil Circuit Breaker Working Principle When a fault occurs, the breaker contacts open in oil, an arc is struck between them. Due to the heat
The performance of a DC motor can be judged by its characteristics and a motor for any particular application can be selected easily. The performance characteristics of DC motor are: Torque versus armature current (T v/s Ia) Speed versus armature current (N v/s Ia) Torque versus speed (T v/s N) Characteristics of DC Motor While
The speed control of dc series motor can be obtained by using various methods shown in the figure. Following few facts about the DC series motor should be kept in mind while studying DC series motor speed control. The current flowing through the armature and field winding of a DC series motor is same. The
Before discussing the speed control of dc shunt motor, we have to find the factors affecting the speed of a DC motor. The speed equation of a DC motor shows that, N α Eb / φ or N α (V – IaRa)/ φ But the resistance of armature winding is small. Therefore the voltage drops IaRa will be