Define circuit breakers
A device designed to open and close by non-automatic means, and to open the circuit automatically on a pre-determined condition
What is another name for a pilot light that comes in different colors?
Indicator lamp
In the case of magnetically opened contacts, the normal state occurs when the operating coil is ______.
deenergized
A common use of a latching relay is in the rotor circuit of a wound rotor motor.
False
OSHA does not require that a person whose work requires them to work on energized equipment to have specialized training.
False
Name three types of fuses
- Standard one time fuse
- Time delay or dual element
- Current limiting
Name three types of circuit breakers
- Non automatic
- Magnetic
- Thermal
- Thermal-magnetic
- Ratings molded case
What does ambient temperature affect?
the trip setting of the device
List three types of operators in oil tight units
- Standard flush head
- Extended head
- Mushroom head
- Key lock
Why is a low voltage indicating light bulb preferred?
due to vibration normally present in machines
What is the difference between a drum switch and a selector switch?
The drum switch is bigger in size, number of contacts and positions.
What is basically a communication carrier that is also used as a power amplifier?
A relay
The ______ is really nothing but a memory relay.
latching relay
The ______ has a distinct advantage when changing relays without disturbing the circuit wiring.
plug-in relay
What is generally constructed in a similar fashion to a relay?
a contactor
The coil of the contactor is generally what voltage?
120 V
What is the difference between a contactor and a motor starter?
A starter has a separate overload protection provided.
What device has a timing function after the timer has been energized or de-energized?
A time delay relay
