Circuit Breakers Flashcards
Which K-Line breakers are not equipped with bell alarms?
Vital pressurizer heater breakers Breakers without secondary disconnects Containment Temp Power breakers Containment MCC redundant breakers
Identify Part Number 3
Claw Gear
Name the five basic categories of circuit-interruption devices found in the power system
- disconnect switches
- air break switches
- load break switches
- power fuses
- circuit breakers
What is the range of voltage considered “High Voltage?”
>15kV, generally used for generation and transmission
What is the volatage range for voltages considered “Medium Voltage?”
Less than or equal to 15kV but greater than 600V
What is considered “Low Voltage” in power systems?
600V or less, generally used to directly supply loads
Define “Voltage Rating” for circuit breakers
Voltage rating is based on the highest RMS voltage at which a device is designed to operate. The voltage level must not be routinely exceeded, as this is the insulation level
Define “Frame Rating”
The maximum continuous current ratings in amps of all parts except the overcurrent device.
Some breakers have a mechanical interlock to prohibit insertion of a different rated breaker into a cabinet.
Define Continuous Current Rating
A current value equal to or less than the frame rating.
This value of current is the rating of the overcurrent device.
It is possible to have a 100 amp frame cirucit breaker that has a continuous current rating of only 40 amps. Overloads and faults are considerably higher but is is not considered continuous.
Define “Interrupt Rating”
The highest current at rated voltage the device can interrupt without external damage.
Typical ratings range from 10000 to
65000 amps symmetrical.
Name the three general classifications of circuit breakers
- Air Circuit Breakers
- Oil Circuit Breakers
- Gas Circuit Breakers
The current ratings does DCPP utilize on the
480V K-Line Breakers?
- 1600 amp - for supply and tie breakers (from load centers)
- 600 amp - for distribution feeder breakers
- 600 amp - for large motor control
- 225 amp - for small motor control
Name the four breaker drawout positions
- Connected
- Test
- Disconnected
- Withdrawn
MOC Switch stands for:
Mechanism Operated Switch
The switch changes state as the breaker opens or closes
Identify the following part
Closing Spring Discharge Roller
GE 12kV Vacuum Breaker
Identify the following part
Negative Interlock Roller
GE 12kV Vacuum Breaker
Identify the following part
Positive Interlock Pin
GE 12kV Vacuum Breaker
Identify the following part
Redundant Negative Interlock Roller
GE 12kV Vacuum Breaker
Identify the following part
Trip Latch Blocking Hole
GE 12kV Vacuum Breaker
