# Which element consumes the reactive power

## What does it mean that reactive power is supplied / consumed?

To answer the question: real power is consumed by a circuit. The reactive power is transferred between the circuit and the source.

Active power in W (P) is useful power. Something we can get out of the loop. Heat, light, mechanical power. Power consumed in resistors or motors.

Apparent power in VA (S) is what the source puts into a circuit. The full influence of the circuit on the source.

The power factor is a kind of efficiency pf = P / S for a circuit. The closer it is to 1, the better.

Reactive power in VAR (volts ampere reactive power) (Q) is the power that circulates between the source and the load. Energy stored in capacitors or inductors. But it is needed. For example, inductive reactive power in electric motors forms the magnetic fields to turn the motor. Without them the engine wouldn't work, so it's dangerous to think it's going to waste, but it is.

Capacitors and inductors are reactive. They store energy in their fields (electrical and magnetic). For 1/4 of the AC waveform, energy is consumed by the reactive device as the field is formed. In the next quarter's waveform, the electric or magnetic field collapses and energy is returned to the source. The same applies to the last two quarters, but with the opposite polarity.

For animation information, see Series AC Circuits. It shows all 6 series connections (R, L, C, RL, RC & RLC). Turn on the immediate power supply. When p is positive the source is supplying current. When p is negative, current is sent to the source.

Electricity is consumed for one R. With an L or C, current flows between the source and the device. In an RL or RC, these two relationships are combined. The resistor consumes and the reactive device stores / sends electricity to the source.

The real benefit is having an inductor AND a capacitor in the circuit. The polarity of the leading capacitive reactive power is opposite to the lagging inductive reactive power. The capacitor supplies current to the inductor, which reduces the reactive power that the source must provide. The basis for the power factor correction.

Select RLC in the reference. Note that the source voltage V.S. (Hypoteneuse) is formed from V.R. and V.L.-V.C. . It is less than when formed from V.R. and V.L.

When the capacitor delivers all the power to the inductor, the load becomes ohmic and P = S and pf = 1. The power triangle disappears. The required source current is less, which means that the protection of the wiring and the circuit may be less. The uncorrected power triangle is located in the motor, with additional current coming from the capacitor.

The reference shows series connections, but each C supplies power to each L in the AC circuit, reducing the apparent power that the source must deliver.

To edit... Let's take an example. P = 1 kW motor with 0.707 pf delay with 120 V source.

Before the power factor correction: Q.L. = 1kVAR. and S.1 = 1.42kVEIN (dashed line) Θ1 = 45 ° lagWing like in I limps V.S. by 45 °. i1 = 11.8A.

Increase the power factor to 0.95 lagging by adding the capacitor in parallel with the load.

After factor correction: P and Q.L. still there. Capacitor adds Q.C. = 671V.AR.