What is the power factor of a computer? What is the power factor?

The power factor of the computer refers to the power factor of the power supply that matches it, and a recent study by PC magazine magazine in the United States shows that the typical power factor of the computer is.

Passive PFC is the highest, active PFC can be done is the power factor, not the conversion rate) above, and there are more active power supplies of domestic first-line brands. The highest conversion rate of titanium gold is currently close to not the power factor, it is the conversion rate).

Generally, it is not an industrial area, and the power factor is relatively large, on the left and right.

Power factor. The power factor characterizes the ability of a computer power supply to output active power.

Power is a measure of the transmission rate of energy, and in a DC circuit it is the product of voltage v and current a. In the AC system, it is more complicated: that is, part of the AC current cycles in the load and does not transmit electric energy, which is called reactance current or harmonic current, which makes the apparent power (voltage volt times amps) greater than the actual power.

The power factor is equal to the ratio of actual power to apparent power. Therefore, the actual power in the AC system is equal to the apparent power multiplied by the power factor.

That is: power factor = actual power apparent power.

Only linear loads such as electric heaters and light bulbs have a power factor of 1, and the difference between the actual power and the apparent power of many devices is small and negligible, while the difference is large and important for capacitive devices such as computers. A recent study by PC Magazine in the United States showed that the typical power factor of a computer is that the apparent power (VA) is 50 more than the actual power (Watts)!

2. Apparent power.

Apparent power: i.e., the product of the AC voltage and the AC current.

It is expressed by the formula as: s ui

In the above formula, s is the rated output power, and the unit is VA (volt-ampere); U is the rated output voltage, the unit is V, such as 220V, 380V, etc.; i is the rated output current and the unit is a.

The apparent power consists of two parts: active power (p) and reactive power (q).

Active power refers to the part that does the work directly. For example, to make the light shine, to make the motor turn, to make the electronic circuit work, etc. Because this power becomes heat after doing work, it can be directly felt by people, so some people have an illusion, that is, they regard the active power as the apparent power, but they don't know that the active power is only a part of the apparent power, which is expressed by the formula:

p ＝ scosθ ＝uicosθ ＝ui·f

In the above formula, p is the active power in w (watts); f cos is known as the power factor, and it is the phase difference when the voltage and current are not in the same phase at the time of a nonlinear load.

Reactive power is the part of power that is stored in the circuit but does not do work directly, and is expressed by the formula:

q ＝ ssinθ ＝uisinθ

In the above formula, q is the reactive power, and the unit is var.

The standard comparison table of power factor is as follows:

1. The power factor standard is 0.9, which is suitable for high-voltage power supply industrial users above 160 kVA (including community industrial users), high-voltage power supply power users equipped with load adjustment voltage adjustment devices and high-voltage power supply power drainage and irrigation stations of 3200 kVA and above.

2. The power factor standard is 0.85, which is applicable to other industrial users of 100 kVA (kW) and above (including non-industrial users of 100 kVA (kW) and above and power drainage and irrigation stations of 100 kVA (kW) and above.

3. The power factor standard is 0.8, which is applicable to agricultural users and wholesale users of 100 kVA (kW) and above, but large industrial users are not classified as wholesale users directly managed by the Electric Power Bureau, and the power factor standard should be 0.85.

Basic overview: power factor refers to the ratio of active power to apparent power, and is generally represented by symbols, that is: =p s.

In a sinusoidal AC circuit, the power factor is equal to the local macro cosine value of the phase difference ( ) between voltage and current, denoted by the symbol cos. At this point, cos =

A power factor meter is an instrument that measures power factor in a single-phase AC circuit or a three-phase AC circuit with symmetrical load balancing. Common power factor tables include electric system, ferromagnetic electric system, electromagnetic system and converter type.

The power factor is normal. The power factor refers to the ratio of the active power of the AC circuit to the apparent power. Under a certain voltage and power, the higher the value, the better the benefit, and the more the power generation equipment can be fully utilized.

The magnitude of the power factor is related to the load nature of the circuit, such as the power factor of the resistance load of incandescent bulb and resistance furnace is 1, and the power factor of the circuit with inductive load is generally less than 1. Power factor is an important technical data of the power system. The power factor is a factor that measures the efficiency of electrical equipment.

The power factor refers to the ratio of useful work to apparent work in an AC circuit, usually expressed by the symbol cos, where is the phase angle in the circuit pin lifting. Here's how to calculate the power factor:

First, determine the useful work (p) and apparent work (s) of the circuit. Useful deficit work is the power in a circuit that is actually used to produce a useful effect, such as the power used to drive an electric motor or to produce illumination. Apparent work is the product of all the total power in a circuit, i.e., voltage multiplied by current.

Calculate the power factor using the following formula:

Power factor = useful work (p) apparent work (s).

The resulting power factor is a value between 0 and 1. If the power factor is close to 1, it means that the useful work of the circuit is relatively high, while the invalid power is low, which is a good power factor. If the power factor is close to 0, it means that the invalid power of the circuit is relatively high and the useful power is relatively low, which is a poor power factor.

Note that when calculating the power factor, you need to make sure that you use a power value in the same unit as the corresponding branch, such as watts (W) or kilowatts (kW). In addition, the power factor is commonly used in AC circuits and not in DC circuits.

1. The transformer itself has no specific requirements for power factor. The power industry stipulates above. 2. The power factor is related to the load nature of the circuit, such as the power factor of incandescent bulbs, resistance furnaces and other resistance loads is 1, and the power factor of circuits with inductive loads is generally less than 1.

Power factor is an important technical data of the power system. The power factor is a factor that measures the efficiency of electrical equipment. The low power factor indicates that the reactive power of the circuit for alternating magnetic field conversion is large, which reduces the utilization rate of the equipment and increases the power supply loss of the line.

3. Transformer is a device that uses the principle of electromagnetic induction to change the AC voltage, and the main components are the primary coil, the secondary coil and the iron core (magnetic core). The main functions are: voltage conversion, current conversion, impedance conversion, isolation, voltage regulation (magnetic saturation transformer), etc.

According to the use, it can be divided into: power transformer and special transformer (electric furnace transformer, rectifier transformer, power frequency test transformer, voltage regulator, mining transformer, audio transformer, intermediate frequency transformer, high frequency transformer, impact transformer, instrument transformer, electronic transformer, reactor, transformer, etc.). Circuit symbols often start with t.

Example: T01, T201, etc.

About the power factor.

Power factor is a data used to measure the power efficiency of electrical equipment (including generalized electrical equipment, such as transformers, transmission lines, etc.) of the power grid.

The formula for defining power factor: power factor, active power, apparent power.

Active power is the power consumed by the device and converted into other energy.

Reactive power is the amount of energy that keeps equipment running, but does not consume. It exists between the power grid and the equipment, and is an indispensable part of the energy of the power grid and equipment. However, if the reactive power is occupied too much by the equipment, it will cause the efficiency of the power grid to be low, and at the same time, a large amount of reactive power is transmitted back and forth in the power grid, which makes the line loss high and the waste is serious.

In order to reduce the reactive power transmission of the power grid, the user is required to provide reactive power to the equipment at the power end, and this behavior of providing reactive power is reactive power compensation. The compensation equipment that provides reactive power is called: reactive power compensation device.

For example, the ATBX local compensation box of Shenzhen Aote Electric Appliance Company is a very effective local compensation device.

Other: What you must know:

Apparent power, let's often call power capacity. Calculation: Square of apparent power Square of active power + Square of reactive power.

The apparent power, active power, and reactive power are in a right-angle triangle relationship.

Note: In the absence of harmonics, it is possible to derive: the power factor cosa (cosine of the angular difference between voltage and current).

The power factor is one of the important technical data of AC circuits. The level of the power factor, right.

It is of great significance for the utilization rate and analysis of electrical equipment, and the study of electric energy consumption.

The so-called power factor refers to the two ends of any two-terminal network (a circuit with two contacts with the outside world).

The voltage u is the same as the current i in it

The cosine between the bit differences.

The amount of work expended in a two-terminal network.

Rate refers to the average power, also known as active power, which is equal to.

It can be seen from this that the power p consumed in the circuit depends not only on the voltage v and the current i.

size, but also related to the power factor. The magnitude of the power factor depends on the load in the circuit.

Quality. For resistive loads, the bit difference between voltage and current is 0, therefore, of the circuit.

power factor max (); In a pure inductive circuit, the bit difference between voltage and current is 2, and it is a voltage lead current; In a pure capacitor circuit, the bit difference between voltage and current is

2), that is, the current leads the voltage. In the latter two circuits, the power factor is 0.

For a general-duty circuit, the power factor is between 0 and 1.

Generally speaking, in the two-terminal network, improving the power factor of the consumer has two significance: first, it can reduce the power loss on the transmission line; Second, it can give full play to power equipment.

such as generators, transformers, etc.). Because the electrical appliances are always at a certain voltage u and one. Fixed active power p

works under conditions, by formula.

It can be seen that if the power factor is too low, it is necessary to use a larger current to ensure the normal operation of electrical appliances.

At the same time, the transmission current on the transmission line increases, resulting in an increase in Joule heating loss on the line.

In addition, the voltage drop in the resistance of the transmission line and the inner group of the power supply is related to the electrical appliance.

The current is proportional to the current that increases the voltage loss inside the transmission line and the power supply.

Lose. Therefore, by increasing the power factor of the electrical appliance, the transmission current can be reduced, which in turn can be reduced.

Power loss on a transmission line.

Calculation of the power factor:

In an AC circuit, the cosine of the phase difference ( ) angle between voltage and current is called work.

The rate factor, denoted by COS, is numerically equal to the ratio of active power to apparent power, or.

The ratio of resistance to impedance.

Namely. cos p s=p (u i)=(i2r) (u i)=r z average power factor active power (active power2 reactive power2) 1 2 active.

Power Apparent power.