Power factor



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what is Power factor

Power factor in an AC electric system in the ratio of real power to apparent power, according to a term that is a value between 0 and 1.. The real power is the ability of a consumer to convert electrical energy into other forms of energy shows the apparent power of the difference between voltage and current is created. Depending on the type they can look over and the reactive power can be more real.
Low power factor (apparent power to be real large) increase the current to flow in a circuit, resulting in increased losses in the circuit. In essence, power factor and efficiency of the effective functioning of shows. The power factor is high, the efficiency is higher.

Active and reactive loads

Overall consumer in an AC circuit can be in terms of electrical energy consumption in two categories: 1-consumers active (resistive)2-consumers reactive (capacitive or inductive) Different types of consumer electrical circuits behaviors manifest differently, for example by converting electrical energy into another form of active consumers of energy, electrical energy consumption. This behavior is slightly different reactive consumers because the consumer rather than electrical energy consumption to save energy. This stored energy in Germany will remain until the Germans by a current or voltage of the power supply is constant. At the end of the feeding process, the consumer begins to compensate reactive power is reduced so that the stored energy again returns to orbit.As a consumer of energy, and this energy circuit until the maximum or peak hold in your wave. To reduce the power load, this time, your energy - which, according to the type of load can be voltage or current - in the circuit returns this energy back into orbit will follow the special effects that will pay them.

The concept of lagging and leading

In a grid AC, the voltage across the capacitor charges continuously changing (the capacitor with this change, opposition) and makes the voltage to the current is lagging. In other words, the current lagging the voltage, so the machine manufacturer reactive power inductive loads Gvynd.v in this case is exactly the opposite of the current and voltage phase and is so pure ohmic load current and voltage are in phase with each other.

Power factor

Purely resistive circuits, including consumers (such as incandescent lamps, electric heaters, electric ovens, etc.) power factor equal to 1, while on the circuits with reactive loads (such as capacitors, motors, transformers, etc.) F be less than one. Power factor once according to the angle between current and voltage can be Pyshfaz or Psfaz. To indicate the direction of the angle of the positive or negative sign is used. Inductive loads such as electric motors or transformers behind current waveform voltage, while capacitive loads such as capacitor banks or Kablhayzyr ground in this case is just the opposite so that the current waveform of the voltage waveform is ahead. However, both types of energy bars in your store with the difference that the energy in the magnetic field induced loads and loads of capacitive energy stored in electrostatic field.

Calculate the power factor

If you are pure sine waves, P, Q and S can be considered three sides of a triangle and thus can be achieved in such a ratio between:

Measurement of power factor

Power factor in a single-phase circuit (or a balanced three-phase circuits) can be measured by a voltmeter Mprmtr- Vatmtr-. So that can be obtained for W (real power), the product of voltage and current apparent power divided. In fact, the power factor is achieved over time. The power factor in a three-phase circuit can be measured in this way. To measure the power factor can also be used a direct measurement of the power factor. Analog type device is composed of two electro-rotating frame. The rotating frame connected in parallel to the circuit. If the two frames A and B called A-frame in the way of a resistor and inductor are placed in the way of Frame B is a stand so the B to the A frame is delayed. If the power factor is 1, the flow in the circuit A frame angle and therefore maximum torque occurs in the frame A and the maximum power factor and power factor will be determined so 1. The power factor is zero, current flow in the circuit B-frame angle and therefore in this case there will be a maximum torque which represents the minimum power factor. The power factor measurement device according to the ratio between the amount of torque in the power factor determines the frame.Another type of device for direct measurement of power factor digital devices. These devices measure the time difference between the current and voltage waveforms or measurement of apparent power and real power to recognize the power factor. The first - the difference between current and voltage measurements - can be used only if that is the sine waveform of current and voltage. In the true power factor loads such as rectifiers using this method will not measure.