Skip to main content

Select preferred language from 'Translate' hidden side menu =>

Blog Navigation

By
                              Blog Navigation 
Post a Comment

Power Factor in an Electrical Circuit Explained (Simple Guide)

Image
By

What Is Power Factor in Alternating Current? Definition, Importance and Effects on Electrical Systems. Why reactive power is generated is explained. 

You go to Starbucks and order a cup of Cappuccino coffee.

Beer mug analogy of a Power Factor:

A beer in a mug shows the analogy of real power, reactive power and total power.



You realise that you paid money for a full cup of coffee, but got a little less due to froth floating on top.

Imagine a coffee vending machine as an ‘electricity generation’ and a ‘cup’ utility of the electricity. ‘Froth’ as reactive power and ‘coffee’ as real power (KW).

The point is, due to froth, you are getting less coffee, although the coffee vending machine is capable of filling a full cup.

Similarly, due to reactive power, ‘electricity generation’ becomes less efficient as its full potential is not being used.

Why is reactive power generated?

Where does this reactive power come from?

Resistive load: 

Voltage and current in phase for the resistive load

In a resistive circuit, voltage and current are in phase. Pl observe, if you multiply current by voltage on the positive side of the wave, you get positive power. If you multiply current and voltage on the negative side, you still get a positive power as -I x -V = + P. Here, positive power means it flows from generation to the utility and gets utilised fully.

Inductive load:

When a generator supplies power to an Inductive load, the situation is not so happy

Voltage current not in phase for inductive load.

Current lag voltage. Pl observe the portion of the waveform intersected by the red vertical line. Positive current is multiplied by negative voltage, generating a negative power, which is the main cause of reactive power. Here, negative power means it flows from the Inductive load back to the generation. You may call it reflected power, which is not being utilised by the load.

Is reactive power a villain?

Is this reactive power a villain? No.

Can an electric motor function without generating a magnetic field? No.

So, reactive power is an unavoidable, integral operational part of the inductive load that can not be avoided, but can be compensated for by adding a capacitor parallel to the inductive load.

Waste of power due to Inductive load. How a power Factor correction reduces power waste

Improved Power Factor makes generation efficient:

Improved power factor makes the generation and distribution of electricity) efficient.

How improved power Factor makes power generation efficient

FAQ Set:

Q1: What is the power factor in AC circuits?
Power factor (PF) is the ratio of real power (watts) used by a load to the apparent power (volt-amperes) supplied, indicating how effectively electrical power is being used.

Q2: What is the range of power factor?
Power factor ranges from 0 to 1:

  • PF = 1: All supplied power is effectively used (ideal).

  • PF < 1: Some power is wasted due to reactive components like inductors or capacitors.

Q3: What affects power factor?
Power factor is affected by reactive loads, such as motors, transformers, and inductive or capacitive devices that cause current to lag or lead voltage.

Q4: Why is power factor important?
A low power factor increases current in the system, leading to higher energy losses, voltage drops, and higher electricity bills. Improving PF reduces these issues.

Q5: How is power factor calculated?
PF = Real Power (W) / Apparent Power (VA)
Alternatively, PF = cos(φ), where φ is the phase angle between current and voltage.

Q6: How can the power factor be improved?
Power factor can be improved using capacitors, synchronous condensers, or power factor correction devices to offset reactive power.

More content related to this:

If you like my answer, consider supporting us:

Comments

Post a Comment

Popular Posts

Blog Navigation

By
                              Blog Navigation 
Post a Comment
Read more

What Happens to an Inductor’s Stored Energy When Current Stops?

By
Can the Energy Stored in an Inductor Be Used Practically? Applications, Benefits, and Real-World Examples. Why does an inductive load create sparking across contacts?  An inductor stores energy in the form of a magnetic field as long as current is flowing through it. As the current stops, the magnetic field began to collapse. Collapsing magnetic flux is also a rate of change of magnetic flux that will induce a large voltage spike (back EMF) across it. Energy stored in an Inductor:  Since this induced voltage is parallel to the inductor coil, it decays by converting it to heat across the coil resistance. In that process, the coil generates a magnetic field again due to the flow of decaying current through the coils, which results in electromagnetic interference in the radio operation and sparking across open contacts. Adverse effects of stored energy in an inductor:  Can we put this back-EMF into use? Yes. Practical Use of Stored Energy in an Inductor:  Spark-ignition...
Post a Comment
Read more

The Role of a Speaker Enclosure in Sound Quality (Explained)

By
Why Do Speakers Need Enclosures? Role in Sound Quality, Bass Enhancement, and Acoustic Performance Explained The sound emitted by the speaker at the front and back is exactly 180 degrees out of phase. If the enclosure is not used to isolate backwards radiated sound, it will cancel sound at the front by destructive interference. That will reduce speaker output greatly. Bass reflex port: Some ported enclosures use backwards radiated sound efficiently by phase shifting it by 180 degrees and radiating it from the front (or back), which adds up to the front sound by constructive interference. This increases speaker output, especially in the low-frequency range. More content related to this: Why are capacitors used in speakers? Why is speaker polarity important? Role of a magnet in a speaker FAQ Set: Q1: What is a speaker enclosure? A speaker enclosure is a box or housing that surrounds a speaker driver to control sound radiation and improve performance. Q2: Why are enclosures important for ...
Post a Comment
Read more

What is the definition of a DC bias voltage in electronics?

By
What is DC Bias Voltage used in Electronic circuits? — Definition, Importance & Practical Examples DC bias is simply a deliberate addition of a DC voltage to a (circuit) node to offset its operating voltage level. Voltage divider bias in a common emitter amplifier:  The most common and popular example of DC bias is the voltage divider bias in a common-emitter amplifier. What will happen if the DC bias is not given to the base of the above circuit? The transistor will act like a rectifier; it will amplify only the positive part of the signal, creating a distorted output that we don't want. Purpose: The purpose of the DC bias in the above circuit is to keep the base DC offset voltage sufficiently high to keep the base-to-emitter junction forward-biased all the time, considering the subtractive effect of the negative-going excursion of the AC input signal and power supply voltage variations. The typical value is 1.2V for the 12V VCC. Biasing is not always DC; it can be AC: AC bias...
Post a Comment
Read more

How Snubber Circuits Protect Relay Contacts from Damage

By
How Do Snubber Circuits Protect Relay Contacts? Working Principle, Benefits, and Design Tips. Explained the Snubber analogy with a shock absorber.  What is 'Snubber'? A snubber circuit is a combination of a resistor and a capacitor. Why switch contact wears out that controls the inductive load? Relay contacts tend to wear out more if it is used to switch an inductive load. When the relay contact opens, the falling magnetic field generates a high voltage spike that results in a spark across the relay contact. A snubber is connected in parallel to the contact. The snubber absorbs the voltage spike. The resistor dissipates the energy stored in the capacitor when the contact closes. Analogy of Snubber:  A Snubber can be compared with the shock absorbers of a car. A spring acts like a capacitor that absorbs shock by compressing, and a damper acts like a resistor that dissipates energy stored in the spring into heat. Both in combination absorb shocks. FAQ Set: Q1: What is a snubber ...
Post a Comment
Read more