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By adding capacitors or inductors in series (typically lower power) or parallel (higher power power factor correction); the choice of capacitor or inductor depends on whether the reactive resistance is "leading" or "lagging". A capacitor is modelled 1/jCw, where w = frequency in rads; an inductor is modeled jLw. If you know the reactive resistance, and the system frequency, you can calculate how much capacitance/inductance is needed.
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∙ 14y ago
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∙ 11y agoReactive power from a generator can be reduced by reducing the terminal voltage (or changing taps on the step up transformer), or reducing the field current. Switching out lightly loaded lines and using parallel reactor banks on transmission systems will reduce the available reactive power.
If what you are meaning is how can the reactive power used by a machine be reduced, that's a different topic and will depend on the machine. Usually the reactive requirements of a machine are not modified (which would require physical changes to the machine), but extra reactive power is added to the system in the form of parallel capacitors.
Wiki User
∙ 10y agoA resistive load puts no reactive power load on the supply. An inductive item like a motor which has windings and a magnetic field loads the supply with reactive power as well as real power.
Reactive power is power that flows from the supply for half of the ac cycle and flows back for the other half. Thus it puts a current load on the supply without drawing power, so it wastes power in the wire resistance of the supply.
In such a case, a capacitor can be placed in parallel with the load, allowing the reactive power to be exchanged locally with the capacitor and not with the supply. This reduces the reactive power drawn from the supply.
A poor power factor can be completely corrected if the capacitor draws the same reactive power measured in VAR (volt-amps reactive) as the inductive load. This is equivalent to forming a resonant circuit resonant at the supply frequency, with the capacitive reactance equal to the inductive reactance. In this case the power factor of the motor and capacitor combined is 1.
A capacitor can also be used for partial correction of the power factor, for example from 0.75 to 0.9.
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When load on a normally excited synchronous motor is increased its power factor tends to what?
approach unit
What is the difference between lagging and leading power factor?
Power factor is the ratio of watts (true power) to VA (volt-amperes, also called apparent power). Where the load is resistive only, the power factor is one, or unity, because the voltage waveform and the current waveform are in phase. Thus, for resistive loads only, true power and VA are the same. Where the load is reactive, the load stores energy, releasing it during a different part of the cycle. This shifts the current waveform so that it is offset, or out of phase with the voltage waveform. Reactive loads can be inductive (electric motors), capacitive, or non-linear (rectifier power supplies). When the load is inductive, the inductance tends to oppose the flow of current, storing energy then releasing it later in the cycle. The current waveform lags behind the voltage waveform. When the load is capacitive, the opposite occurs, and the current waveform leads the voltage waveform. So, lagging vs. leading is another way of saying the net reactance is either inductive or capacitive. This is slightly simplistic, and what we are talking about above is really DPF, or Displacement Power Factor. Non-linear loads don't really shift the current waveform, they distort it. The current waveform starts to look like a square wave, and square waves contain harmonics. So non-linear loads add harmonic distortion, and this tends to mimic a capacitively reactive load, adding some leading power factor. So when we say power factor, we really must include DPF plus harmonic distortion in total. One memory aid that may help to remember all this is: ELI the ICE man The L in ELI means inductance. The E (voltage) comes first, then the I (current) lags behind. Inductive reactance produces a lagging power factor. The C in ICE means capacitance. The I (current) comes first (leads) then the E (voltage) comes later. Capacitive reactance produces a leading power factor. Remember, it's always the current waveform that is affected by the reactive load, so you have to think about whether the current is leading or lagging. Most reactive loads are inductive, so at most sites the PF is lagging. One cool tidbit is that capacitive reactance cancels out inductive reactance. So if we have a building full of motors, we can add a bunch of capacitors to improve our power factor, meaning we get as close to unity as we can. Thus we have power factor correction capacitors that are made just for this purpose.
Explain how you can determine the type of correlation for a set of data pairs by examining the data in a table without drawing a scatter plot?
"If y tends to increase as x increases, then the data have a positive correlation. If y tends to decrease as x increases, then the data have a negative correlation. If the points show no correlation, then the data have approximately no correlation."
Why do you connect a capacitor panel to the load?
Capacitors are sometimes connected in parallel to inductive loads to improve the power factor, raising the voltage of the source AC. Power factor is the ratio of apparent power over true power. It is 1, if the load is purely resistive, such as in a toaster, but it is less than 1 if the load is reactive, such as in a motor. This is because current is not in phase with voltage in that case. Inductive loads cause the current to lag voltage, and capacitive loads cause the current to lead voltage. Placing capacitors across an inductive load tends to compensate for the lagging power factor. Specifically, power factor is the cosine of the phase angle between voltage and current. In an ideal situation, with perfect sources, conductors, and reactive loads, the phase angle would be plus (capacitive) or minus (inductive) 90 degrees, and the power factor would be zero. This means that a conventional watt meter would register zero but, in reality, energy is still being supplied, and that has to be accounted for. In practical terms, since conductors have impedance, a poor power factor degrades voltage so, adding capacitors raises voltage.
Suppose a wire of resistance R could be stretched uniformly until it was twice its original length. What would happen to its resistance?
Current tends to travel on the surface of the wire. As you decrease the cross-sectional area of a wire the resistance increases. That is why larger wires are rated for higher currents.
The of a circuit tends to slow down the movement of electrons?
The "impedance" of a circuit slows down the movement of electrons. This can be resistive, reactive or a combination of both.
How does reactive power change the Power Factor?
Power Factor is the relationship between the phase of the current and voltage which are each sine waves. When there is an inductance in a circuit the AC current waveform tends to lag the voltage. This causes a phase difference which reduces the Power Factor from a maximum of one to something less.
Does alcohol consumption tends to decrease or increase self awareness?
Decrease
The total amount of usable energy tends to increase in a closed system?
No. It tends to decrease.
How reactive is zinc?
zinc is very reactive, if you leave zinc out in air, it will oxidize, that's how reactivie it is.
How reactive is osmium?
Osmium has varying states of reactivity. Its pure state tends be quite reactive and is rarely used unless alloyed. Osmium tetroxide is extremely reactive, whereas osmium dioxide has very little reactivity.
Which aspect of culture tends to decrease rates of conformity?
Individualism tends to decrease rates of conformity within cultures. In individualistic cultures, there is a greater emphasis on personal freedom, independence, and unique expression, which can lead to decreased pressure to conform to group norms.
What period of time tends to decrease as cultivation becomes more intense?
The fallow period tends to decrease as cultivation becomes more intense. Fallow is the period of time where fields are left uncropped to allow the soil to recover and restore its nutrients. In intense cultivation systems, fallow periods are often shortened or eliminated to maximize crop production.
How does criminal behaviour change with age and sex?
Criminal behavior tends to decrease with age.
What tends to result in a decrease in the selling price of houses in an area?
An increase in mortgage interest tates.
Why does hemoglobin decrease in hyperthyroidism?
Because hyperthyroidism tends to lead to anemia, which will result in decreased hemoglobin
Which tends to result in a decrease in the selling price of houses in an area?
An increase in mortgage interest rates
