Methods of transmitting electricity:
Direct Current (DC)
Current which flows only in one direction with a constant voltage.
Typical for low voltage applications. E.G. batteries.
Low voltage is less dangerous than higher due to less current through a given resistance.
Equation for DC circuit: P = V x I
P = power in watts
V = voltage
I = the current in amps
Alternating Current (AC)
Electricity has nearly no inertia so direction of flow can be rapidly reversed by reversing the voltage.
Voltage plotted out looks like a sine wave
Amount of power is more difficult to calculate since the Current flow may lag behind the voltage reversal.
Power factor = the cosine of the angle between the voltage wave and the resultant current wave.
Expressed range of 0.0 to 1.0, also shown as a percentage.
Single phase
Single phase circuit power formula: P = V x I x PF
P = power in watts
V = voltage in volts
I = current in amps
PF = power factor in decimal form
Three-phase
(contains three different circuits, each 120deg out of phase with the other and one neutral ground
Three phase circuit power formula: P = V x I x PF x (square root of 3)
P = power in watts
V = voltage in volts
I = current in amps
PF = power factor in decimal form
Square root of 3 = 1.73
Wattage
Kilowatt = 1,000 watts
Megawatt = 1,000,000 watts
3,350 watts = 3.35 kilowatts
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