Power Relationships 030201e Flashcards
What are the formulas for power in an AC circuit?
P = V(r) x I(r)
P = I(r)^2 x R
P = V(r)^2 / R
What are the other names that can be used for power?
Real power.
Active power.
In phase power.
True power.
What is power defined as in an electrical circuit?
Rate at which work is being done or the rate at which energy is converted from one form to another.
What is reactive power and what is it also called?
Quadrature power or out-of-phase power.
The rate at which energy is stored and returned to the circuit.
What is the symbol for reactive power and what is it measured in?
Symbol is Q.
Measured in volt-amperes reactive (VAR)
What impact does increasing or decreasing inductance have on reactive power?
If inductance is increased > Inductive reactance increases > current decreases > reactive power decreases.
If inductance is decreased > Inductive reactance decreases > current increases > reactive power increases.
What impact does increasing or decreasing capacitance on a circuit do?
If capacitance increases > capacitive reactance decreases > Current increases > Reactive power increases.
If capacitance decreases > capacitive reactance increases > current decreases > reactive power decreases.
How is total reactive power calculated?
Qx = Qxl - Qxc
What is the main difference between the two types of reactive power when it comes to energy exchanges in a circuit?
They take place at exactly opposite times. 180 degrees out of phase from each other.
How is power factor calculated?
Power (P) / Apparent power (S).
PF = P / S
What is a power factor of one referred to as?
Unity power factor.
Which means power and apparent power are equal as they are in a purely resistive circuit.
Define the term power factor?
Is the ratio between power and apparent power.
The property of an electric circuit that converts energy to heat is?
Resistance.
