Electrical Flashcards
What are the top connections called of a junction box?
Line lugs and they are hot all the time
What is electromagnetism?
The interactive relationship between electric charge and magnetic flux
What is permeability?
The ease at which a material can be magnetized by a solenoid is a measure of its permeability
What is the best conductor?
Silver but it’s very expensive
What are the 2 types of semiconductors?
N-type
P-type
What is correct current?
The flow of free electrons in the conductor all flowing the same direction
What is alternating current?
Current flowing in a circuit from a source of voltage that changes polarity (direction of current flow) continuously and regularly.
What is single-phase?
A single voltage that creates a potential difference between only two conductors
What is three-phase?
Three different voltages that interact to produce potential differences between the three conductors that supply the three-phase loads.
What can voltage be compared to in electrical terms?
Pressure
What is the symbol for volts in a mathematical equation?
E
What can amps be compared to in a hydraulic system?
Flow
What is the symbol for amps in a mathematical equation?
I
How many watts is 1 hp?
746 watts
What is the formula for calculating watts?
P = I x E
What is a series circuit?
Current that flows through 2 lamps in tandem.
What is a parallel circuit?
Current that flows through a divided path
What is the formula for calculating voltage?
E = I x R
What are 4 factors that affect resistance?
Materials
Cross-sectional area
Length of conductor
Temperature
What is resistance compared to in a hydraulic circuit?
Flow restriction
What is a capacitor compared to in hydraulics?
An accumulator
What is the alternating current wave called?
A sine wave
How far must you be when working near overhead power lines?
7m (22 feet)
What are the tree types of circuit breakers?
Single-pole, single-phase
Three-phase auxiliary
Motor circuit breakers
What position are the contacts in on a stop button?
Normally closed when depressed
What is an electrical interlock?
They prevent electrical equipment from operating out of sequence
What are the two distinct types of fuses?
Fast acting
Time delay
How must you check amperage with a multimeter?
Between 2 points of a circuit that are normally connected to one another
What is a must-requirement for testing with an ohmmeter
All power to the circuit must be off
What is a megohmmetor used for?
For testing insulation of motor windings or other wiring installations
In a 120V AC single-phase, two-wire supply circuit. What colours are the wires?
Black is hot
White is neutral
Natural copper/green is ground
In a 120/240 volt AC, single phase, three-wire supply circuit. What colours are the wires?
Hot wire 1 is black
Hot wire 2 is red
Neutral is white
Ground is natural copper/green
For smaller wire, the ________ the gauge number, the _______ the wire
For smaller wire, the HIGHER the gauge number, the SMALLER the wire
