Mikey’s Flashcards
Electric energy measured in
Joules
Apparent power
Is the vector sum of true power plus reactive power. Volt x Amp = VA
Electrical resistance
Measure in ohms. R = V/I
Power
Ability of electrical energy to do useful work in the form of heat; making light, making motion
True power
Power available for useful work
Electrical pressure, EMF, measure in
Volts
Eddy currents
Energy lost, caused by allowing an induced current to flow in the core material. Can be eliminated by a laminated core
Hysteresis
Energy lost caused by reversing the magnetic field in the core as magnetizing ac current rises and falls
ELI the ICE man
ELI- volt leads current in an inductor
ICE- current leads voltage in a capacitor
Waveform starting to the right of zero?
Lagging
Power factor
When true power is equal to the apparent power the PF = 1 or 100%
Electrical inductance is measure in
Henrys
Ac voltage opposition by a capacitor is measure in
Capacitive reactance
Short circuit
Zero resistance, maximum current flow, voltage at short is zero
Open circuit
Infinity resistance, zero current, full voltage across open
Good diode
Will register a value of .3 or .7 with leads in one direction and OL with leads opposite
Bad diode
Will register OL in both directions or a value of 0.00 in both directions
Delta Current
I line = I coil x 1.732
Wye current
I line = I coil
AC voltage- Peak Voltage
1.414 x Vrms
AC -
V peak to peak
V peak x 2
Single phase Apparent Power
1ph AP
AP = V coil x I coil
Kilo
10 to the 3rd
1000
Mega M
10 to the 6th
1,000,000
Giga G
10 to the 9th
1,000,000,000
Milli m
10 to the -3
.001
Micro u
10 to the -6
When working with a CT …
Ground the secondary
R = V/I
Circuit resistance is directly proportional to applied voltage and inversely proportional to current flow
CT Burden
Secondary load of a current transformer
Iron Losses
Losses due to hysteresis AND eddy currents
Copper losses
Energy lost due to the ohmic resistance of the primary and secondary windings
In a capacitive circuit with Ac applied the AC voltage _______ the AC charging current by 90 degrees
Lags
Ac voltage
Constantly changing. Pulling and pushing force that cause free electrons to move back and forth
Nano n
10 to the -9
.000000001
Electrical capacitance is measured in
Farads
3 phase Apparent Power
3 x Vcoil X Icoil
Or 1.732 x Vline x I line
Which logic gates has output if both inputs are zero?
NAND, NOR, XNOR
I’m a pure resistive circuit with AC voltage and current applied, the ac voltage and the ac current are ______ .
In phase
I secondary =
I secondary = I primary x TR x Efficiency
How much resistance do you want to find during a transformer insulation test
Expected resistance would be infinite
Turns Ration, TR formulas
Np/Ns = Vp/Vs = Is/Ip
Use coil values
Waveforms starting to the left of zero are?
Leading
Ac current
Flow of free electrons measured in amperes
In an inductive circuit with ac applied, the ac voltage _____ the ac current by 90 degrees.
Leads
What is the combination of reactance and resistance measured in?
Impedance
Dc voltage
Positive pulling and negative pushing force. Dc does not change polarity
Ac current opposition by an inductor is measure in…
Indicative reactance
Dc current
Free flow of electrons between two points of different polarity
Electrical conductance is measure in
Siemens
Electrical work is measured in
Watts
I = V/R
Current flow is directly proportional to voltage and inversely proportional to resistance
V = IR
Voltage is directly proportional to current and resistance
TRANSFORMERS
Delta configurations
I line = I coil x 1.732
V line = V coil
