Engine power factor: definition, ways to increase "cos phi"

The power factor of a motor, referred to as "cos phi", is usually tried to do as much as possible. The lower the value, the greater the current must have in order to allocate the required power in the circuit. If you make a mistake in the calculations, then electricity consumption will inevitably increase, and the efficiency will, on the contrary, decrease.

An important indicator

Cosine phi is an indicator of devices powered by electric current. This is a parameter that characterizes the distortion of the AC waveform. In mathematical terms, this indicator can be characterized as the ratio of active power to total power. The higher the value, the more efficiently the device uses energy.

To explain the physical meaning of the coefficient, as an example, you can take the calculation of other related parameters for one of the devices. Let's say:

1. An ideal capacitor was included in the AC mains.
2. Since the alternating voltage periodically changes its polarity, the device will then be charged, then again return the stored energy to the source.
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3. As a result, electrons will circulate.

In DC power grids, power, like other key parameters, remains unchanged for a certain period. For such cases, the concept of power is applicable, which is the product of two important parameters of the current - its strength and voltage. However, this cannot be said about the alternating current, because its parameters are constantly changing. That is why you cannot simply determine the value from the power factor formula used to determine it in the case of a DC power grid. For this reason, such a concept as instantaneous power was introduced.

Instant power

This indicator is directly related to the release of energy and to mechanical work: that is, to those phenomena that are of an inertial nature. It is used exclusively for calculations. In assessing the calculations of various indicators of electrical networks, the effective values ​​of the current and voltage are also used.

Measuring instruments familiar from the school bench - volt and ammeter - designed to measure these values. An indicator such as total power, in fact, is the product of the effective current and voltage: you just need to multiply them.

This indicator is used in determining the requirements of the electrical network. It is not measured in watts, for this there is a special unit of measurement with a name that directly indicates what exactly needs to be multiplied to determine the value - volt-ampere.

Active and reactive

With the advent of reactive elements in the power grid, changes begin to occur. These elements can store energy and then return it. As a result, the so-called reactive power is formed. However, she does not do any useful work. Of course energy returns with some losses, therefore, in any power grid, they try to minimize the reactive value.

Active power is the averaged instantaneous value over a certain time period. She is capable of doing useful work. To determine the total, you need to square the active and reactive and then extract the square root from the sum of these squares.

The active one can be found by multiplying the current strength, voltage and cosine phi. If it is equal to one, then the active power will fully correspond to the full one. This will mean that there is no energy loss at all, and any work is useful.

The efficiency in this case will be 100%. This happens only on an active load, in a network where there are no reactive elements. Therefore, with reactive power, no work is performed, however, losses occur, which have an inversely proportional dependence on the cosine phi. The closer the value is to one, the less the loss.

Increase value

The cosine phi can be increased either with the help of special compensating devices, or without them. The first method involves streamlining the process, which improves the energy regime. Special electrical measuring devices help to determine the coefficient.called phase meters.

Increasing the value of cosine phi in electricalare trying to achieve three main goals:

1. They want to save energy in this way.
2. Increasing the cos phi also helps to save the material used to make the conductors. This is also a savings.
3. A high value of the indicator indicates a high efficiency.

The cosine phi indicator must be taken into account when creating power grids. If it is not high enough, it will inevitably lead to huge energy losses.