Switches, Fuses, and Circuit Breakers Flashcards
A ______ is a device that is used to Open or Close a current path.
The switch is a device that is used to Open or Close a current path.
What is the meaning for these schematic symbols?
What does “NO” or “NC” mean?
Normally Open (NO) or Normally Closed (NC).
A Normally Closed switch is opened only while being depressed.
A Normally Open switch is closed only while being depressed.
A switch that opens or closes one current path is called what?
A switch that opens or closes one current path is called a Single Pole (SP).
A switch that opens or closes two current path is called what?
A Double Pole (DP) switch
Whats the difference between a double throw and a single throw?
A Single Throw (ST) can route current in only one path.
The Double Throw (DT) switch can route current in either of two paths.
What are the two types of protection devices?
Fuses and Circuit breakers
What happens if current exceeds the limit set by a fuse?
The wire in the fuse heats up and melts and the circuit opens
Fuses are rated in what?
amps
What is the schematic symbol for the fuse?
What is the schematic symbol for the circuit breaker?
Circuit breakers are classified as what?
Magnetic circuit breakers produce a magnetic field as current flows through the device. When current flow exceeds the limit set by the device, the magnetic field opens the circuit breaker.
Thermal circuit breakers operate on the principle of temperature. Current flow produces heat. Too much current flow overheats the bimetallic element, causing the circuit breaker to open.
