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Topic: Power factor correction

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	Power factor correction - Wikipedia, the free encyclopedia
		Power factor correction may be applied either by an electrical power transmission utility to improve the stability and efficiency of the transmission network.
		Power factor correction returns the power factor of an electric AC power transmission system to very near unity by switching in or out banks of capacitors or inductors which act to cancel the inductive or capacitive effects of the load.
		Power factor correction is achieved by complementing an inductive or a capacitive circuit with a (locally connected) reactance of opposite phase.
	en.wikipedia.org /wiki/Power_factor_correction (1108 words)

	Power Factor Correction technology and Calculations
		Power factor is the ratio between the KW and the KVA drawn by an electrical load where the KW is the actual load power and the KVA is the apparent load power.
		Power factor correction is achieved by the addition of capacitors in parallel with the connected motor circuits and can be applied at the starter, or applied at the switchboard or distribution panel.
		The Power factor of the total current supplied to the distribution board is monitored by a controller which then switches capacitor banks In a fashion to maintain a power factor better than a preset limit.
	www.lmphotonics.com /pwrfact.htm (3440 words)

	POWER AND POWER FACTOR IN AN AC CIRCUIT
		Power in an AC circuit is the vector sum of true power and reactive power.
		Power factor is the ratio of true power to apparent power in an AC circuit.
		Power factor is unity when there is no reactive power or when inductive reactance and capacitive reactance are equal, effectively cancelling eachother.
	www.geocities.com /vijayakumar777/powerfactor/powerfactor.html (4198 words)

	A Primer on Power Factor Correction
		Power factor is the proportion of active power (p) to apparent power (s), as shown in this power triangle.
		This graph of the release of the power system in per-unit of active power in a facility demonstrates that you get the maximum release in those cases where the existing power factor is low and the target power factor is high, such as near or equal to one.
		If the reactive power requirement for the capacitor bank, as calculated using Equation B, is greater than the average value previously calculated using Equation A, then the capacitor bank sized for the average value won't be sufficient for compensating the reactive power of the load when the active power reaches its maximum value.
	ecmweb.com /mag/electric_primer_power_factor/index.html (2578 words)

	Power Factor Correction Concepts
		This Apparent Power (VA) has two components; one is the Active Power (W) actually being consumed by the lamp for illuminating it, and the other is the Reactive Power (VAr) feeding the electromagnetic circuit of the control gear.
		Power factor is the ratio of Active Power (W) to the Apparent Power (VA) (Figure 1).
		The leading power factor on the first ballast, in conjunction with the lagging power factor of the second ballast, brings the total power factor to near unity.
	www.ambercaps.com /lighting/power_factor_correction_concepts.htm (684 words)

	Lessons In Electric Circuits -- Volume II (AC) - Chapter 11
		Because true power and apparent power form the adjacent and hypotenuse sides of a right triangle, respectively, the power factor ratio is also equal to the cosine of that phase angle.
		Power factor can be an important aspect to consider in an AC circuit, because any power factor less than 1 means that the circuit's wiring has to carry more current than what would be necessary with zero reactance in the circuit to deliver the same amount of (true) power to the resistive load.
		Poor power factor in an AC circuit may be “corrected”, or re-established at a value close to 1, by adding a parallel reactance opposite the effect of the load's reactance.
	www.ibiblio.org /obp/electricCircuits/AC/AC_11.html (3514 words)

	Digital Control of Power Factor Correction
		Note that although the load being powered in Figure 1 is resistive, the load presented to the power line is far from resistive.
		Power factor correction (PFC) is an active electronic technique to present a "nice" sinusoidal load to the power line regardless of the final load's characteristics.
		For the purpose of the PFC circuit, the AC line voltage is actually the output of the transformer winding between pins 4 and 6.
	www.embedinc.com /pfc (5061 words)

	PFC decoded
		Power factor correction (PFC) is, essentially, what you do to complex AC loads (such as PC switchmode power supplies) to make them act more like simple loads (such as toasters).
		Power equals VA times power factor, and power factor is the cosine of the phase angle between voltage and current.
		It sucks power from the mains in a resistive way, and feeds it to the low power factor circuit on the other side, isolating the mains from whatever that circuit is doing.
	www.dansdata.com /gz028.htm (1670 words)

	Power Factor Correction
		Power factor correction capacitors are often rated in kVar, instead of uF, because that is how the power company works.
		Only if the power factor were very poor, so the reactive impedance was quite large (and the corresponding capacitance low) would series compensation seem to be useful.
		This is why power factor correction is usually done in the distribution network at MV or HV, and not at the end voltage.
	home.earthlink.net /~jimlux/hv/pfc.htm (1098 words)

	Power Factor Correction
		Utility rate structures that account for reactive power consumption, by either a KVA or var demand usage, or a power factor penalty are the ones that can provide this pay-back.
		The reactive power, or magnetizing power, (represented by the vertical leg of the upper or lower triangle) is the power required to produce the magnetic fields to enable the real work to be done.
		The ratio of the real power to the total power in the equation above (or the cos of phi) is called power factor.
	www.nepsi.com /powerfactor.htm (984 words)

	NOTE 307 - POWER FACTOR CORRECTION (PFC) TESTING
		Because of that, reducing power source harmonic current, increase power factor is a global environmental protection trend.
		Passive type use inductor (figure 2), capacitor (figure 3) circuitry to reduce harmonic current, because power source frequency is 50Hz or 60Hz low frequency, it needs large inductor and capacitor, also the power factor improvement is not as good, limited improvement result, that is why it is rarely use.
		To have a universal voltage model, this power factor regulator is a very important additional value, and this power factor regulator output of 380Vdc has a 10Vp-p and 50/60Hz harmonic and high frequency noise.
	www.imcpower.com /prodigit/an_307.htm (1215 words)

	Application Guide - Power-factor Correction Capacitors
		Three of the most important factors to consider when choosing a bypass capacitor are its impedance, its dissipation factor, and insulation resistance.
		Power-Factor-Correction is the practice of raising the power factor of an inductive circuit by inserting capacitance.
		Power supplies receive "power" from an AC source such as a commercial power line, a motor driven generator or an inverter.
	www.electrocube.com /support/bullet3.asp (750 words)

	Technoserve - Power Factor Correction
		Power Factor (PF) is simply a name given to the ratio of "Actual" Power (the Active Power) being used in a Circuit, expressed in Kilowatts (kW), to the power which is "Apparently" being drawn from the line expressed in kilo volt-amperes (kVA).
		The Power Factor is therefore Unity or 1.
		Therefore, the current flowing in an AC circuit (unless corrected) is generally larger than is necessary to supply the power being expended by the plant.
	www.technoserve.co.za /power_factor_correction.htm (421 words)

	POWER FACTOR CORRECTION
		Reactive power charges can be made significantly smaller by the introduction of Power Factor Correction Capacitors which is a widely recognised method of reducing an electrical load and minimising wasted energy, improving the efficiency of a plant and reducing the electricity bill.
		Capacitive Power Factor correction (PFC) is applied to electric circuits as a means of minimising the inductive component of the current and thereby reducing the losses in the supply.
		The introduction of Power Factor Correction capacitors is a widely recognised method of reducing an electrical load, thus minimising wasted energy and hence improving the efficiency of a plant and reducing the electricity bill.
	www.energy-in-motion.com /PFC.html (676 words)

	Power factor - Wikipedia, the free encyclopedia
		By definition, the power factor is a dimensionless number between 0 and 1.
		When power factor is equal to 0, the energy flow is entirely reactive, and stored energy in the load returns to the source on each cycle.
		Power factors are usually stated as "leading" or "lagging" to show the sign of the phase angle.
	en.wikipedia.org /wiki/Power_factor (1562 words)

	Power Factor Correction
		Power Factor Correction is the term given to a technology that has been used since the turn of the 20th century to restore Power Factor to as close to unity as is economically possible.
		Power Factor Correction is the process of compensating for the "lagging" current by applying a "leading" current in the form of capacitors.
		The actual value of the term "power factor" is the ratio of the force represented by the diagonal line divided by the total force represented by the towrope.
	www.save-energy.org /power_factor_correction.htm (858 words)

	Power Factor, Power Factor Correction, Capacitors, Power Quality
		Therefore, the kW=kVA, and the Power Factor = 1 (unity).
		Thus, power is lost in the magnetic field and kW < kVA, and the Power Factor < 1.
		This will effectively eliminate any charges assessed by the local utility for low power factor and will prevent the system from going into capacitance (current leads the voltage) during low load situations.
	www.hersheyenergy.com /PowerFactor.html (247 words)

	Power Factor Correction
		As far as the source is concerned the apparent power is the power that must be provided to the circuit.
		If this were the case the power factor would be 1 (unity) or 100 percent.
		The expression "correcting the power factor" refers to reducing the reactance in a circuit.
	www.tpub.com /neets/book2/4k.htm (320 words)

	Power Factor Correction Capacitors
		Power factor is the relationship between working (active) power and total power consumed (apparent power).
		When low power factor is not corrected, the utility must provide the nonworking reactive power in addition to the working active power.
		By supplying their own source of reactive power, the industrial user frees the utility from having to supply it; therefore, the total amount of apparent power (kVA) supplied by the utility will be less.
	www.galco.com /circuit/harmon.htm (416 words)

	X-bit labs - Articles - X-bit Presents: Power Supply Unit Testing Methodology (page 8)
		The following kinds of power are generally recognized in alternating current circuits: 1) instantaneous power is the product of the currant by the voltage in the particular moment of time; 2) active power is the power generated on a purely resistive load and is measured watts.
		Power factor is the ratio of active power to full power, i.e.
		As the result, the PSU is consuming power from the power grid in short pulses, approximately coinciding with the peaks of the sinusoid of the voltage in the power grid:
	www.xbitlabs.com /articles/other/display/psu-methodology_8.html (633 words)

	Power Supplies 101: A comprehensive guide Motherboards.org
		Some people say that power factor correction makes a power supply more efficient, but as you should now know, for a power supply to be more efficient it needs to pull less wattage from the wall.
		If we were to switch this power supply out for one with active PFC and a power factor of.99, assuming it's the same efficiency at your typical load, you're only pulling 303VA from the wall.
		And this use of power becomes less with the higher your input voltage is (because you draw less amperage at higher voltages and less amperage means less resistance.) This is why some power supplies in the EU, where 230V is used, they will sell 230V only APFC power supplies.
	www.motherboards.org /articles/guides/1487_9.html (911 words)

	Power Factor Correction Capacitors
		There are many factors that can influence the harmonic content but typical harmonic currents, shown as a percentage of the fundamental current, are given in the above table.
		Whenever power factor correction capacitors are applied to a distribution network, which combines capacitance and inductance, there will always be a frequency at which the capacitors are in parallel resonance with the supply.
		When there is a need to vary the power factor correction component of a harmonic filter, careful consideration of all load parameters is necessary.
	www.galco.com /circuit/PFCC_har.htm (1836 words)

	Directory:Power Factor Correction - PESWiki
		In fact, because the unit draws continuous power, even when no power is being called from the home, the unit can end up resulting in more power used, not less.
		Power factor correction is usually used in industrial settings, where large inductive load exists; in which case tremendous power savings are realized, as well as greater longevity of the appliances.
		The only time power factor correction is really helpful in a home power setting, is if there is an unusually high inductive load, such as from a pool pump, or a koi pond pump.
	peswiki.com /index.php/Directory:Power_Factor_Correction (380 words)

	Active PFC (Power Factor Correction)
		Because Active PFC uses a circuit to correct power factor, Active PFC is able to generate a theoretical power factor of over 95%.
		Active Power Factor Correction also markedly diminishes total harmonics, automatically corrects for AC input voltage, and is capable of a full range of input voltage.
		Passive PFC uses a capacitive filter at the AC input to correct poor power factor.
	www.endpcnoise.com /cgi-bin/e/pfc.html (295 words)

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