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Rated power factor
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∙ 10y ago
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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.
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.
How many KVA of genset to produce 10000watts?
A gen set will be rated for a certain kVA at a certain power factor, or certain kW at a certain power factor. If rated in kVA, the power factor indicates the amount of real power you will get (ie if rated at 10,000kVA at .95 pf, the gen set can generate .95 x 10,000kW, or 9,500kW).
What is rated voltage in generators?
it is mentioned by the manufacturer
Why a rotor of an alternator at rated power dissipates more heat at a low power factor load than at a high power factor load?
at lower power factor current drawn by load is high and at higher pf the current drawn is less...
Can we improve generator power factor for increasing active power?
The 0.8 Power Factor provided by generator manufacturers is not the load power factor, but it is the nominal power factor used to calculate the kW output of an engine to supply the power for a particular alternator kVA output. Alternators are therefore designed to supply their rated kVA at 0.8 lagging power factor.
Why the transfermer rating is in KVA where as generator rating is KW?
Transformers are rated based on the amount of current flowing through them, irrespective of whether the current is in phase with the voltage or not, thus KVA. When it comes to generators, what the owner is interested in is how much real power the generator can deliver (watts). Most generators are rated at a specific real power and a power factor (often .95).
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.
Why the rotor of an alternator at rated power dissipates more heat at a low power factor load?
In an alternator, the load current is supplied by the stator and the excitation is applied to the rotor. When the power factor is low (lagging), more excitation is required to maintain rated output voltage at rated current. More excitation is also required to maintain rated output voltage with increased output current. Increased excitation current means increased rotor losses that must be dissipated as heat. (akash)
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.
Why are generators rated in watts?
Generators are rated in watts because watts are the scale on which energy is measured.
What is the best brand for power generator that I can buy on the internet?
The following website has a list of the top ten rated generators. In addition to this list, I have seen other references to the Champion brand being a top rated generator. http://www.squidoo.com/top-rated-backup-generators
Why transformers rated in MVA not in MW?
Transformers are rated in KVA and MVA. The load determines the power factor. It is obvious to multiply the VA with cosine angle to get Watts or Kilo watts. While manufacturing the transformer or at its installation we don't know the load power factor. Hence we could not determine the rating in Watts or kilo watts or Mega watts. We simply note it as VA or KVA. S.Dhanabal
How many KVA of genset to produce 10000watts?
A gen set will be rated for a certain kVA at a certain power factor, or certain kW at a certain power factor. If rated in kVA, the power factor indicates the amount of real power you will get (ie if rated at 10,000kVA at .95 pf, the gen set can generate .95 x 10,000kW, or 9,500kW).
Why ups rated in kva?
The kva rating includes the power factor of the connected load.KW * Power Factor = kva.AnswerThe above answer is incorrect, as it's actually kV.A x power factor = kW.The answer is straightforward, the output of the UPS is the product of its rated output voltage and its rated output current, and the product of voltage and current is 'apparent power', expressed in volt amperes.
What is rated voltage in generators?
it is mentioned by the manufacturer
What equipment used in power factor improvement?
The simplest method of power-factor improvement is by using appropriate capacitors, connected in parallel with the load. Power-factor improvement capacitors are rated in reactive volt amperes, not farads.
