Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
A circuit breaker is
Power factor correcting device
A device to neutralize the effect of transients
A waveform correcting device
A current interrupting device
A current interrupting device
A circuit breaker is a mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also making, carrying for a specified time, and automatically breaking currents under specified abnormal circuit conditions such as those of a short circuit. It serves as the primary protection mechanism to isolate faulty sections of an electrical power system.
A circuit breaker is a mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also making, carrying for a specified time, and automatically breaking currents under specified abnormal circuit conditions such as those of a short circuit. It serves as the primary protection mechanism to isolate faulty sections of an electrical power system.
VrestrikeтАЛ=VpeakтАЛ(1тИТcos(╧ЙnтАЛt)) тАФ Represents the transient recovery voltage across breaker contacts
When a fault is detected, the relay sends a trip signal to the circuit breaker's operating coil. The breaker contacts separate, and an arc is formed between them due to the ionization of the medium. The circuit breaker mechanism then uses techniques like arc quenching (via oil, air, SF6, or vacuum) to extinguish the arc, thereby interrupting the flow of fault current.
Circuit breakers operate automatically when relay contacts close due to fault detection.
The primary challenge in high-voltage interruption is the extinction of the electric arc.
Circuit breakers are classified based on the medium used for arc extinction (Oil, Air, Vacuum, SF6).
They must withstand high recovery voltage after the current reaches zero.
Provides automatic protection against faults.
Allows for manual control of power distribution.
Requires periodic maintenance for contact erosion.
Relatively higher cost compared to simple fuses.
Transmission line protection
Transformer substations
Industrial distribution panels
Arc quenching is essential because, without it, the current would continue to flow through the ionized path even after contacts separate.
Options A, B, and C describe static devices or power conditioning equipment, whereas a circuit breaker is a mechanical protection device.
D is correct тАФ A circuit breaker is essentially a mechanical switching device designed to interrupt fault currents to protect power system equipment.
In competitive exams, always distinguish between protective devices (Circuit Breakers/Relays) and power conditioning devices (Capacitor banks/Filters).