What does power factor mean?

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Power Factor
In AC systems, "Power Factor" is the ratio of volt-amps to watts. To get volt-amps, you also multiply volts times amps. With a resistive load, such as an incandescent lamp, volts times amps equals watts. All of the power gets dissipated heating up the lamp filament to make it glow. In this case, volt-amps is equal to watts, giving a ratio of 1:1, or 100%. With inductive loads like transformers, electric motors, fluorescent lamps, etc., there is very little resistance. Something called "reactance" limits current flow. Larger currents flow with little power being dissipated. With a power factor of 50%, double the current would flow. For example, a 40 watt incandescent lamp draws 0.33 amps. (40 watts / 120 volts = 0.33 amps) This bulb, being a resistive load, has a power factor of 100%. A single tube fluorescent lamp rated at 40 watts may draw double the current of the 40 watt incandescent, but still only use 40 watts of real power. This fixture has a power factor of 50%.

Additional Input from Contributors:
  • Power Factor, simply put is a % of how efficiently the AC power is being used.
    THIS DOESN'T MATTER IN HOUSEHOLD ELECTRICITY. If a factory has a Power Factor of 95%, then it will draw 105% of the current it would draw if it were at 100%, or a Powerfactor of 1 (also called unity).The electric companies charge large industrial customers more for inefficient systems, i.e. Power Factor lower or higher than 1 (100% efficient). They do not charge individual homes for this, so you can't save money by correcting your power factor.
  • It's a ratio of AC volt-amperes to AC watts
  • Electrical meters for homes measure only resistive (real, apparent, or actual) power. They do not measure reactive power.
  • In a study of alternating current (that which supplies our homes and businesses in the United States), it will be observed that there are alternating waves of both voltage and current. In a circuit with purely resistance load, the waves of current and voltage are in exact phase relationship to each other. This means that when the voltage is at its peak, the current flow is at its peak as well. An inductive load (that is, a coil) causes the current wave to lag or fall behind the voltage wave, so that the peak current flow is some time after the voltage wave is at its peak level. A capacitive load (that is, a capacitor) causes the current wave to lead or advance ahead of the voltage wave, so that the peak current flow is some time in advance of the peak of the voltage wave.The consequence of this is that the AVAILABLE REAL POWER is the relationship between the current and voltage waves.
  • Resistive circuits have a power factor of 1.0, or unity, because the waves are in phase. The more out of phase the relationship between voltage and current, the less efficient the use of available power, the more "waste" energy.The less efficient the use of energy, the larger the size of transmission and generating equipment required to provide for energy needs and the more costly the operation of utilization equipment.
  • Power Factor is the relationship between Current and Voltage in an electrical supply With a power factor of 1 power equals Volts multiplied by Amps (I=VxA)


Also see the related Question WHAT IS REACTIVE POWER? by clicking on the link below:
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What is a power factor?

The Power Factor is an indicator of the quality of design andmanagement of an electrical installation. It relies on two verybasic notions: active and apparent power. The active power P (kW) is the real power transmitted toloads such as motors, lamps, heaters, and computers. The electricalactive power is transformed into mechanical power, heat orlight. In a circuit where the applied r.m.s. voltage is V rms and the circulating r.m.s. current is I rms , the apparent power S (kVA) is the product: V rms xI rms . The apparent power is the basis for electrical equipmentrating. The Power Factor λ is the ratio of the active power P (kW)to the apparent power S (kVA): The load may be a single power-consuming item, or a number of items(for example an entire installation). The value of power factor will range from 0 to 1.

What is power factor?

The Power Factor is an indicator of the quality of design andmanagement of an electrical installation. It relies on two verybasic notions: active and apparent power. The active power P (kW) is the real power transmitted toloads such as motors, lamps, heaters, and computers. The electricalactive power is transformed into mechanical power, heat orlight. In a circuit where the applied r.m.s. voltage is V rms and the circulating r.m.s. current is I rms , the apparent power S (kVA) is the product: V rms xI rms . The apparent power is the basis for electrical equipmentrating. The Power Factor λ is the ratio of the active power P (kW)to the apparent power S (kVA): The load may be a single power-consuming item, or a number of items(for example an entire installation). The value of power factor will range from 0 to 1. Power factor is the ratio of apparent versus true power. It is the cosine of the phase angle between voltage and current. In a resistive load, the phase angle is zero, so the power factor is one. In a theoretically perfect reactive load, inductive or capacitive load, with zero resistance conductors, the phase angle is -90 degrees (inductive, lagging) or +90 degrees (capacitive, leading) so the power factor is zero.

What does a Lagging power factor mean?

underdamped Answer A lagging power factor describes a situation in which the load current is lagging the supply voltage. This describes an inductive load, such as a motor, etc.

What does unity power factor UPF mean?

Unity power factor has a value of 1.0. This means the current and voltage waveforms are in phase. This is only possible if the net load is non-reactive (resistive). If the load is either capacitively or inductively reactive, the power factor will be other than unity.. If an inductively reactive load such as a motor is offset by a capacitively reactive load such as a PF correction capacitor, it is possible to acheive a net load that has unity power factor.. Some loads, such as resistance heaters, are intrinsically non-reactive, and present a unity power factor.

How do you get power factor?

Single phase PF = Input Watts/Volts x Amps. Three phase PF =Input Watts/Volts x Amps x1.732. Additional Answer You can determine the power factor of a circuit using three instruments: a voltmeter , and ammeter , and a wattmeter . Multiplying the voltmeter reading by the ammeter reading will supply the value of the apparent power in volt amperes. The wattmeter reading will supply the value of the true power in watts. Divide the number of watts by the number of volt amperes, and that will indicate the power factor of the circuit.

What does it mean to have a power factor of 1?

\n. \n. \nFirst we need to know what is power factor ? \nit's cosine of angle between the current and voltage at that point where we wish to measure it.\nso power factor of "1" means the angle between the voltage and current is 0 degree. It means literally that the current and voltage is in the same phase.

What do you mean by wattless current and power factor in AC?

Watts = Current x Voltage x Power Factor In an AC circuit both the voltage and current are sine waves. When they are in phase (waveforms lie over top of one another) the PF is one. As they become out of phase the PF decreases to zero. This happens when the phase difference is 180 degrees. In this case the positive peak of current is at the same place in time as the negative peak of voltage or vice versa. So when PF is zero you coul say you are getting zero watts. Answer An a.c. load current can be resolved into two components. One, in phase with the supply voltage, and responsible for supplying true power to the load. The other, at right angles to the supply voltage, and responsible for supplying reactive power (e.g. the magnetic field, in the case of a motor). As reactive power is sometimes termed 'wattless power', we can say that the second component of this current is 'wattless current'.

What do you mean leading power factor?

A leading power factor means that the current is leading thevoltage. That means that in the AC cycle (50 or 60 Hz) the currentreaches its peak before the voltage. The amount of phase-lead canbe up to 90 degrees which means one quarter cycle, or 5milliseconds in a 50 Hz system.

What do you mean lagging power factor?

A lagging power factor means that the current is lagging behind thevoltage. That means that in the AC cycle (50 or 60 Hz) the currentreaches its peak after the voltage. The amount of lag can be up to90 degrees which means one quarter cycle, or 5 milliseconds in a 50Hz system.

What is the meaning of poor power factor?

Power factor is the cosine of angle between voltage and current that we all know. And the power factor should be unity or close to unity. Unless if we have the power factor not close to unity or far away from unity is called poor power factor. This termed as poor because it will take large amount of current for the given power. If the large amount of current is drawn from the substation or anything else then the line loss will increase. Line loss is (I^2)R loss. So the current increase line loss will also be increased. So as to avoid such losses every industry should maintain their power factor(Normally in every Industry they maintain .9 and above). Those who are not maintaining power factor will be fined.

What actually you understand the meaning of power factor?

In a.c. circuits, there are two different 'types' of 'power': 'true power' and 'reactive power'. 'True power' describes the rate at which the energy supplied to a load is either lost to the surroundings through heat transfer or which does useful work (such as providing the output from a motor), and we measure this in watts. 'Reactive power' describes the rate at which energy is alternately stored in the load's magnetic or electric fields and, then, returned to the supply as the current increases and decreases every quarter-cycle, and we measure this in reactive volt amperes. Some books describe reactive power as the rate at which this energy 'sloshes back and forth, between the supply and the load's magnetic or electric fields', because it represents the movement of energy but not a loss of that energy! For a given load, reactive power increases as the phase angle (the angle between the load current and the supply voltage) increases. Obviously, therefore, the greater a load's reactive power, the greater its apparent power. The 'total' rate at which energy is moving in an a.c. circuit is the vector sum of true power and reactive power, and we call this the circuit's 'apparent power', expressed in volt amperes. Power factor is simply the ratio between true power (expressed in watts) and apparent power (expressed in volt amperes) or the cosine of the phase angle. Loads with low power factors (i.e. large phase angles) draw far more current than is necessary for the energy consumed from the supply. So, low power-factor loads require unecessarily-large supply conductors if higher-than-normal voltage drops and line losses are to be avoided and are, therefore, undesirable.

What mean power factor 0.26 lead?

When looking at power factor, it is the ratio of watts (true power) to VA. The power factor is how we measure power systems. A person with a low power factor like .26 will have a higher electricity bill.

What does in a power the number used as a factor mean?

Numbers with exponents are sometimes referred to as a power. Forexample, x^4 can be called "x to the fourth power" which means thatx is used as a factor four times. So, in a power, the number usedas a factor is the base.

What does power factor means?

In an AC circuit the power is often less than the voltage times thecurrent, and the power factor describes how much less. A resistive load has a power factor of 1 but an induction motormight have a power factor of 0.7 so the power is equal to the voltstimes the amps times 0.7. Power companies do not like a poor power factor because it placesan undue load on the power system that the companies receive norevenue for, because consumers are normally billed for the trueenergy consumed. High-power users like factories may be billedextra if they present a poor power factor, which might induce themto improve the power factor.

What does zero leading power factor mean?

A 'leading' power factor indicates that the load current is leading the supply voltage. Since power factor is the cosine of the angle by which the load current either leads or lags the supply voltage (i.e. the load's phase angle), a cosine of 0 corresponds to a phase angle of 90 degrees. So, a power factor of 0 (leading) indicates that the load current is leading the supply voltage by 90 degrees, which means that the load must be purely capacitive.