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
In medium voltage circuit breaker contact pressure is ______.
kg
kg
12 kg
15 kg
kg
In medium voltage circuit breakers, the contact pressure is a critical parameter to ensure low contact resistance and prevent localized heating. For standard medium voltage air or vacuum circuit breakers, a contact pressure of approximately 5 kg is typically maintained.
In medium voltage circuit breakers, the contact pressure is a critical parameter to ensure low contact resistance and prevent localized heating. For standard medium voltage air or vacuum circuit breakers, a contact pressure of approximately 5 kg is typically maintained.
FpressureтАЛ=kтЛЕ╬Фx тАФ where k is the spring constant and ╬Фx is the compression distance.
The contact pressure is maintained by calibrated springs known as contact pressure springs. These springs ensure that the fixed and moving contacts remain in firm contact during the closed state, preventing arcing at the contact interface due to high resistance or electromagnetic repulsion forces during fault current conditions.
Contact pressure minimizes I2R losses at the connection.
Prevents contact welding during fault current passage.
Required pressure depends on the rated current and breaker design.
5 kg is a standard empirical value used for routine maintenance in many MV switchgear models.
Reduces contact surface degradation.
Ensures consistent mechanical stability.
Springs may lose tension over long operational lifecycles.
Requires periodic calibration to maintain specified pressure.
Vacuum Circuit Breakers (VCB)
Air Break Circuit Breakers (ACB)
Lower pressure leads to high contact resistance and potential overheating.
Excessive pressure can cause mechanical wear on the operating mechanism.
A is correct тАФ 5 kg is the standard design contact pressure for medium voltage circuit breaker contacts to ensure efficient current flow.
Always verify the manufacturer's maintenance manual for specific models, as contact pressure requirements can vary slightly based on the breaker's rated interrupting capacity.