O&M Training Center Circuit Breaker Flashcards
Plasma is defined as the state of matter in which electrons are removed from atoms or molecules, creating an electrically conducting gas.
TRUE
The plasma performs what essential function when breaking a circuit?
flow between two open circuits
Why must the air in the breaker high air pressure system be very dry?
Because it’s the insulating medium between contacts
What is the purpose for the SF6 gas in an air-blast circuit breakers?
Insulate the support column current
The purpose of the blast valve is to blow the arc from the stationary fingers to the arcing probe.
TRUE
When is the breaker trip-free?
When It’s closed to a fault
How is the air for breaker operation dried?
Conducting the air up through an automatic drying system
How long does the reactivation process take?
same amount of time as the compressor has run to recharge the receiver
Generally OCB’s are smaller than air-blast breakers of comparable voltage and current ratings.
True
What is the purpose of the auxiliary contacts?
To protect the main contacts from burning by closing first and opening last
How is clean oil made available for interruption in the General Electric type FK OCB?
By a spring-driven pump
As a protective feature a _____
valve is provided to open if the gas pressure within the pressure chamber should become too great during an interrupting operation.
Safety
What is the main drawback of using SF6 gas in a circuit breaker?
After exposed to an electric arc it produces gaseous by-products and powders
How is the interrupter classified?
Multi-break double pressure unit
The “X” - “Y” control scheme used with this breaker is typical. One difference is the introduction of_____ pressure cutout switch in series with the closing circuit.
Low
