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Why you take complex conjugate of phasor current in complex power?
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Why you take the conjugate of current in complex power?
In order to calculate the complex power of a circuit, the conjugate of current is used. The Vrms of the circuit is multiplied by the complex conjugate of the total circuit current.
Why do you use the conjugate of current to calculate power?
Because the angle of the power phasor is the difference between the one of voltaje and the one of current. As they are multiplied,instead of being added they are substracted
Why current increases with decrease in power factor?
It's easier to answer you question the other way around, that is "Why does the load current fall with an increase in power factor?"Before power-factor improvement, the load current is the phasor (or vector) sum of the load's resistive (IR) and inductive currents (IL).Power-factor improvement is achieved by adding a capacitor in parallel to the load so, after power-factor improvement, the load current becomes the phasor sum of the resistive current (IR), inductive current (IL), and the capacitive current (IC).Since the inductive current and capacitive current are displaced from each other by 180 degrees (i.e. are in antiphase), the the phasor sum of IR + IL +IC will be smaller than the phasor sum of just IR and IL.Hence, the supply current reduces as the power factor improves.
What is a phasor diagram and why you draw it?
Theoretically, it can be drawn at any angle. Normally, however. it is drawn along the real, positive, axis (i.e. facing East). For series circuits, the reference phasor is the current and, for parallel circuits, the reference phasor is the voltage. For transformers, it is the flux.
How do you draw phasor diagram of maxwell bridge?
For Series Circuits (example for R-L circuit)Because current is common throughout a series circuit, current is taken as the phasor of reference for series AC circuits. So, we start by drawing a current phasor at 0o. Since the voltage across a purely resistive component (VR) is in phase with the current, we next draw VR in phase with the reference phasor. Since the voltage across a purely inductive component (VL) leads the current by 90o, we draw VL at 90o. We vectorially add phasors VR and VL to give V, the supply voltage. The angle between V and the reference phasor, I, is the phase angle. To create an impedance diagram, divide each voltage by the reference. To create a power diagram, multiply each voltage by the reference.For Parallel Circuits (example for R-L circuit)Because voltage is common across each branch of a parallel circuit, voltage is taken as the phasor of reference for parallel AC circuits. So, we start by drawing a voltage phasor at 0o. Since the current through a purely resistive branch (IR) is in phase with the voltage, we next draw IR in phase with the reference phasor. Since the current through a purely inductive branch (IL) lags the current by 90o, we draw IL at -90o. We vectorially add phasors IR and IL to give I, the load current. The angle between I and the reference phasor, V, is the phase angle. To create an admittance diagram, divide each current by the reference. To create a power diagram, multiply each current by the reference.
Why is power factor is cos of angle between voltage and current?
Power factor is the ratio of true power to apparent power -if you refer to the so-called 'power triangle', these correspond to the adjacent and hypotenuse of a right-angled triangle. The cosine of the angle between them is the ratio of hypotenuse (apparent power) to adjacent (true power). As the power triangle is derived from the voltage/current phasor diagram, this is exactly the same angle as that between load current and supply voltage.
Cross-power spectrum of two fourier transform images?
It's (I1./I2*)/(|I1./I2*|), where I2* is the complex conjugate of the Fourier transformed Image 2
Sketch and explain the no load phasor diagram of a transfomer?
a.) Io = no load current consists of 5% of the full-load primary current. b.) Iom = magnetising current/component responsible for setting up the magnetising flux in the core. c.) Iol = Ic = power loss component responsible for supplying the core losses and the windings losses.
Is the phasor a time-domain or frequency-domain quantiy?
It is a frequency-domain quantity. In Basic Engineering Circuit Analysis by Irwin, the time domain is written as A*cos(wt+/-THETA) and the frequency domain is written as A*phasor(+/-THETA).A series of phasor measurements, taken at regular intervals over time, can sometimes be useful when studying systems subject to variations in frequency. The electric power system is one example. The power grid nominally operates at 50Hz (or 60Hz), but the actual frequency is constantly changing around this nominal operating point. In this application, each individual phasor measurement represents a frequency domain quantity but a time series of phasor measurements is analyzed using time-domain techniques. (http://en.wikipedia.org/wiki/Synchrophasor)
What is the difference between phase angle and phase difference?
Although we use the term 'Phase angle' it's also an angle referred to another phasor (voltage or current).For example,conventionally when expressing power factor, we use 'voltage' as the reference. So the 'phase angle' of a particular phasor is the phase difference between our reference (voltage) & the phasor.As the gist, both mean the same except that 'phase angle' is the direction of the phasor w.r.t. positive x direction (reference)..AnswerBy definition, phase angle is the angle by which a load current leads or lags a supply voltage.Phase difference is the angle between any two electical quantities -for example, the angle two phase voltages of a three-phase system.
How many volts an amps would it take to power a 120 horsepower motor?
Since 1 HP=745.7W, 120 HP=89484W. If you're using DC, then your volt amp combination must satisfy the equation: 89484W=V*I. If you're using AC, then you must satisfy the equation: P=|V|*|I|*cos(ang(V)-ang(I)) P is average power, also known as real power. You want this value to be 89484W |V| is the voltage magnitude in rms (rms is what measuring equipment shows. US residential homes normally have 120V rms) (rms=root mean squared) |I| is the current magnitude in rms ang(V) is the phasor angle of the voltage ang(I) is the phasor angle of the current
When A voltage sourcehaving a source impedance Z R jX can deliver maximum Average power to a load impedance Z?
the impedence should be complex conjugate of an equivalent impedence of the network when viewed from the terminals of the load. i.e; Z=R-jx
