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Q: Why is unity power factor not the most economical power factor?
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Power factor correction capacitors?

Yes, they exist. Capacitors are often used to change a low power factor (such as 0.5) to a higher power factor near unity (1). In some instances, this will lower fees and costs to utilities. In homes, this is not really necessary as most devices used in homes are near unity power factor, or tend to be minor/sporadic loads (such as a washing machine).


When you should use synchronous motor instead of capacitor for power factor correction?

Synchronous motors show some interesting properties, which finds applications in power factor correction. The synchronous motor can be run at lagging, unity or leading power factor. The control is with the field excitation, as described below:When the field excitation voltage is decreased, the motor runs in lagging power factor. The power factor by which the motor lags varies directly with the drop in excitation voltage. This condition is called under-excitation.When the field excitation voltage is made equal to the rated voltage, the motor runs at unity power factor.When the field excitation voltage is increased above the rated voltage, the motor runs at leading power factor. And the power factor by which the motor leads varies directly with the increase in field excitation voltage. This condition is called over-excitation.The most basic property of sycho motor is that it can be use as a CAPACITOR OR INDUCTOR both. Hence in turn it improves the power factor of system.The leading power factor operation of synchronous motor finds application in power factor correction. Normally, all the loads connected to the power supply grid run in lagging power factor, which increases reactive power consumption in the grid, thus contributing to additional losses. In such cases, a synchronous motor with no load is connected to the grid and is run over-excited, so that the leading power factor created by synchronous motor compensates the existing lagging power factor in the grid and the overall power factor is brought close to 1 (unity power factor). If unity power factor is maintained in a grid, reactive power losses diminish to zero, increasing the efficiency of the grid. This operation of synchronous motor in over-excited mode to correct the power factor is sometimes called as Synchronous_condenser.


What is power factor significance in calculating the AC power?

Power Factor is one of most significant parameter in calculating AC Power. As we know it is cosine of angle between AC Voltage and Current it comes in picture while calculating power in AC circuits Power In AC (P) = Voltage (V) X Current (V) X Power Factor Let us take an example of Power with Power factor and without power factor for same circuit. Let Us assume V = 125 Volts I = 1 Amp Power Factor = 1 Then P = 125X1X1= 125 Watts But for any circuit when Power factor is below 1, to execute same power, Circuit has to draw more current. for example P = 125X 1.25 X 0.8 = 125 Watts In first example power factor of the circuit was unity = 1 and in that condition current of the circuit was 1 amp whereas in second example power factor of the circuit is 0.8 due to which current of the circuit increases to 1.25 amp to execute the same power. Now due to increase in current of the circuit many factors are affected like heat loss, Conductor's specification , Class of insulation etc. Thus it can be concluded after going through above explanation that power factor play a significant role in AC power calculation as well as in actual practices.


What is the power factor of an induction motor?

Induction motor comprised inductor as the most part in it and an inductor has the characteristic to oppose the change of current, i.e., it has lagging power factor as current lags behind the voltage. Hence, an induction motor works on lagging power factor.


How do you calculate actual power factor?

The power factor of a circuit is defined as the cosine of the phase angle -which is the angle by which the supply current lags or leads the supply voltage in AC circuits.Power factor is always expressed as either a 'lagging power factor' or as a 'leading power factor'.The terms 'lagging' or 'leading' describe the relationship of the supply current to the supply voltage. Since current lags voltage in an inductive circuit, 'lagging power factors' describe inductive circuits; since current leads voltage in capacitive circuits, 'leading power factors' describe capacitive circuits. In practice, lagging power factors are more common than leading power factors, because most practical loads are inductive (e.g. motors, etc.).Power factors are normally expressed as a decimal (e.g. '0.8 lagging') although, in the past they were often expressed as a percentage (e.g. '80% lagging'). 'High' power factors tend towards unity, whereas 'low' power factors tend towards zero.In terms of power, the cosine of a circuit's phase angle and, therefore, its power factor is the ratio of that circuit's true power (expressed in watts) and its apparent power (expressed in volt amperes).Power factor has no effect whatsoever upon the energy consumed by a load, but it does effect the amount of current drawn from the supply. 'Low' power factors result in unnecessarily-large load currents for any given load, which mean that the supply utilities need to use larger than necessary conductor sizes (expensive!). For industrial or commercial (but not residential) loads, therefore, it is often desirable to 'improve' the load's power factor towards unity, which acts to reduce the load current. This is most-usually done by installing capacitors close to the load, and is termed 'power-factor correction' or 'power-factor improvement'. Capacitors used in this way are rated in reactive volt amperes, rather than in microfarads.

Related questions

Power factor correction capacitors?

Yes, they exist. Capacitors are often used to change a low power factor (such as 0.5) to a higher power factor near unity (1). In some instances, this will lower fees and costs to utilities. In homes, this is not really necessary as most devices used in homes are near unity power factor, or tend to be minor/sporadic loads (such as a washing machine).


When you should use synchronous motor instead of capacitor for power factor correction?

Synchronous motors show some interesting properties, which finds applications in power factor correction. The synchronous motor can be run at lagging, unity or leading power factor. The control is with the field excitation, as described below:When the field excitation voltage is decreased, the motor runs in lagging power factor. The power factor by which the motor lags varies directly with the drop in excitation voltage. This condition is called under-excitation.When the field excitation voltage is made equal to the rated voltage, the motor runs at unity power factor.When the field excitation voltage is increased above the rated voltage, the motor runs at leading power factor. And the power factor by which the motor leads varies directly with the increase in field excitation voltage. This condition is called over-excitation.The most basic property of sycho motor is that it can be use as a CAPACITOR OR INDUCTOR both. Hence in turn it improves the power factor of system.The leading power factor operation of synchronous motor finds application in power factor correction. Normally, all the loads connected to the power supply grid run in lagging power factor, which increases reactive power consumption in the grid, thus contributing to additional losses. In such cases, a synchronous motor with no load is connected to the grid and is run over-excited, so that the leading power factor created by synchronous motor compensates the existing lagging power factor in the grid and the overall power factor is brought close to 1 (unity power factor). If unity power factor is maintained in a grid, reactive power losses diminish to zero, increasing the efficiency of the grid. This operation of synchronous motor in over-excited mode to correct the power factor is sometimes called as Synchronous_condenser.


What is the comparative and superlative form of the word economical?

"economical" has no comparative or superlative form. You would say "more economical" or "most economical."


How can improve the power factor?

To increase capacitive load and decrease inductive loadAnswerThe most common method is to add a capacitor, or a capacitor bank, in parallel with the load. In practise, the reactive power of the capacitor (they are not rated in farads, but in reactive volt amperes) must be a little short of being equal to the reactive power of the load, so that the power factor approaches, but does not equal, unity.


Which geographic factor most limited the growth of Latin American unity of the early 19th century?

the regions diverse landforms


What is the most economical incandescent bulb 10 watts or fluorescent lamp 10 watts and why?

the most economical is the incandescent bulb because the power of bulb is low only while the fluorescent lamp is low and additional the power of ballast from 10%-20% power consumed.but the fluorescent lamp is 5 times brightly the incandescent bulb.


Why alternator power factor 0.8?

In terms of generators, the alternate power factor is generally 0.8 for most models. This factor is defined as the power needed to operate within the limits of he generator capability curve.


What is power factor significance in calculating the AC power?

Power Factor is one of most significant parameter in calculating AC Power. As we know it is cosine of angle between AC Voltage and Current it comes in picture while calculating power in AC circuits Power In AC (P) = Voltage (V) X Current (V) X Power Factor Let us take an example of Power with Power factor and without power factor for same circuit. Let Us assume V = 125 Volts I = 1 Amp Power Factor = 1 Then P = 125X1X1= 125 Watts But for any circuit when Power factor is below 1, to execute same power, Circuit has to draw more current. for example P = 125X 1.25 X 0.8 = 125 Watts In first example power factor of the circuit was unity = 1 and in that condition current of the circuit was 1 amp whereas in second example power factor of the circuit is 0.8 due to which current of the circuit increases to 1.25 amp to execute the same power. Now due to increase in current of the circuit many factors are affected like heat loss, Conductor's specification , Class of insulation etc. Thus it can be concluded after going through above explanation that power factor play a significant role in AC power calculation as well as in actual practices.


What is the most economical transportation in Spain?

The most economical transportation in Spain is the bus system. Trains are also inexpensive.


What is the most important thing to do in life if you are a Hindu?

The most important thing (I think) is to practice Ahimsa.I am not trying to oppose this answer, but we should also teach our people to share love between each. Because unity is power of our nation. If we have power of unity, then nobody can try to cheat us or split us.


What are the two leading countries in the world?

The two most powerful countries in the world are the US and Russia (based on military power) However based on economical power, the US and China.


What is the power factor of an induction motor?

Induction motor comprised inductor as the most part in it and an inductor has the characteristic to oppose the change of current, i.e., it has lagging power factor as current lags behind the voltage. Hence, an induction motor works on lagging power factor.