Circuit Breaker
Circuit Breaker Ratings and Specifications Explained
A circuit breaker's nameplate carries a set of ratings — voltage, current, breaking capacity, making capacity, short-time current and du...
Circuit Breaker
Oil Circuit Breaker vs Vacuum Circuit Breaker: A Complete Comparison
Oil and vacuum were the two great interrupting media of the twentieth century — oil came first, vacuum replaced it at medium voltage. They e...
Circuit Breaker
Circuit Breaker vs Isolator: Differences and Why Isolators Sit on Both Sides
A circuit breaker and an isolator (disconnector) both open a circuit, so beginners often confuse them. In reality they do opposite jobs: the...
Circuit Breaker
Restriking Voltage Derivation and Proof That RRRV Is Proportional to Natural Frequency
When a circuit breaker interrupts a fault, the voltage that appears across its contacts immediately after the arc goes out is called the res...
Circuit Breaker
Resistance Switching: Sequence of Operation and Why ABCBs Need It
When a circuit breaker interrupts a small inductive current — for example, switching off an unloaded transformer or a shunt reactor — the cu...
Circuit Breaker
Circuit Breaker Selection by Voltage Level and the Dielectric Curve
Not every circuit breaker suits every voltage. A breaker that works perfectly at 400 V would fail catastrophically at 132 kV, and a breaker ...
Circuit Breaker
Air Blast Circuit Breaker (ABCB): Working Principle and the Series Isolator
An Air Blast Circuit Breaker does something no oil breaker can: it uses the same blast of compressed air twice — once to move the contacts a...
Circuit Breaker
Minimum Oil Circuit Breaker (MOCB): Advantages and Disadvantages
The Minimum Oil Circuit Breaker (MOCB) was the answer to one simple complaint about the older Bulk Oil Circuit Breaker (BOCB): it used far t...
Circuit Breaker
What Is a Switchyard? Definition and the 7 Switchgear Elements Inside It
A switchyard is one of those places every electrical engineering student hears about but rarely sees from the inside. In simple words, it is...