Lab Flashcards
4 basic types of electrical control drawings
Schematic, wiring, block, interconnection
What is a form “x” contactor
Spst-no-dm
What is a form y contactor
Spst-nc/db
Another name for a non time delay fuse
Single element fuse
2 types of cct breakers
Instantaneous, inverse time
What o/c rating indicates the max curennt can interrupt
Interrupting rating
2 languages of smart relays
Ladder logic
Function block
What are yhe 5 principals proximity switches operate under
Magnetic
Photo electric
Capacitive
Inductive
Ultrasonic
4 factors determining short cct fault chrrent
Kva of trans
%impedence to ground
Voltage on the secondary side of transformer
Cct impedence (disgance from oc)
What is the max percentage of voltage you can supply to a coil
110% of the coil rating
4 main types of electromagnetic relays
Power
Plug in
Industrial control
Low voltage lighting
How many pins average for 1 set of No/NC contacts
3
Whats smaller iec or nema
Iec
Main difference between relays and contactors
Relays handle lower current
What type of relay has exposed contacts
Power relays
What is the purpose of a mechanical interlock
To stop 2 ccts being energized at the same time
How are eddy currents reduced
Laminations in the core
Main disadvantage of copper contacts
Probe to arcing pitting and oxidation
