Phase Definition and 1000 Threads

I am trying to understand space vectors in 3 phase machines. If you have a balanced 3 phase system, the 3 phasors of voltage, current or whatever... should sum to 0. i<0 + i<-120 + i<-240 = 0. But in this image of a rotating space vector ...

Why do we take a particle's position ##x## and its velocity ##\dot{x}## as independent variables in a phase space when they are dependent in the sense that given the function ##x(t)##, we can get the function ##\dot{x}(t)##? I'm thinking they are independent variables but not independent...

A very neat video showing a phase transition in rotating balls in a cup. Serves as a good analogy to other phase transions.

Could you please explain the derivation of group velocity = dw/dk I read ut here https://en.m.wikipedia.org/wiki/Group_velocity Is it approximation, if so under what circumstances

For example, the term angular frequency, it units is radian per second. For phase, it is also measured in radians or degrees, why is that? Why is the math the same when you use angles to describe oscillations?

Hi, We have a machine from Europe with three 400V 50Hz 3 phase motors. Assume we only have 240V single phase available. There may be 480V single phase available. I don't currently know how many poles the motors have. Assume they are not made for both 50Hz and 60Hz as some are. Power consumption...

I have a few questions regarding three phase power measurement Three Watt-meter method: Balanced load: What would happen if the neutral where removed ?, my guess is that it wouldn't make a difference because the neutral doesn't carry any current Unbalanced load: Same question as above Two...

Say you have a circuit component with impedence Z(\omega). Is it possible combine it in some way to resistors, capacitors, and inductors, so as to shift the phase of the impedance by a constant?

See the title. I'm not sure that this is the right place to post this question, but I'm not sure it fits any better on any of the other boards. Let's say you have a phase transition. The correlation length will scale as: ξ = |TC-T|ν This diverges on both sizes of the phase transition. Now...

HI there, First post here, I hope I can get out into the forum and provide some answers to you in the future. I am an Electrician here In Australia and spent my career so far in Industrial. Currently I have a job which is putting me to the test so I thought someone might be able to offer some...

Homework Statement (a)How much heat must be added to a block of 0.120kg of frozen ammonia initially at 100oC to convert it to a gas at 80oC given the following information? (b) assuming this could be done using a reversible process what would be the total entropy change associated with this...

Homework Statement imgur link: http://i.imgur.com/0Zc8nQe.png Homework Equations Y-Delta transformations The Attempt at a Solution Since it's a proof, I can't check the answer in the back. What I did: I transformed the three impedances in their delta config to a Y config, and my TI89...

Hi. I'm trying to simulate two phase flow (gas - solids) in unsteady state in CFD Fluent. After testing many k-e models I'm achieving the same problem - solids have their assumed velocity (12m/s) but after 3,5seconds of real time they pass a distance of 0,5 meters... whereas the first phase...

Homework Statement [/B] imgur: http://i.imgur.com/9ktFGSs.pngHomework EquationsThe Attempt at a Solution [/B] I came up with both 150 and 210 as the difference between the phase angles. I chose 150. If you draw the vectors and compare their angles, the angular difference between them could...

Homework Statement transverse wave is traveling through a wire in a positive direction of the x-axes. Distance od the wire particles in the motion of the wave can be described as ##y(x,t)=53*10^{-6}sin(188t-3.14x)## Find the ratio of the phase wave speed and maximal speed of the wire particles...

I am somewhat confused by what pressure refers to in a phase diagram? In a closed box it makes sense to me that the vapor pressure would eventually equilibriate at a pressure determined by the temperature. However, say you have an open box. It makes sense that the liquid would boil when the...

Can Phase Space be break down into different regions, different regions that are not mixed up with one another, if we do so, the different regions can raise to any conservation of physical quantity?

Homework Statement Homework Equations Wye: V_Line = sqrt(3) x V_Phase Delta: V_Line = V_Phase The Attempt at a Solution My answer doesn't quite match up with the solutions in the book, and was wondering what I went wrong here? Any help is greatly appreciated!

The reason I ask is that the singularity involves a region of spacetime composed of a different order of magnitude than i suppose the region outside the singularity.

hi alll...we know that by changing the polarity of phase and neutral , direction of ac motor can be changed. but is there any automated device that does this job? ...

I'm currently studying wave mechanics(high school level), and more thing that makes scribble all over is the concept of phase and Phase difference. After these long tries, I could mathematically think of what they are, but cannot geometrically or logically express it. Can someone help me out...

If there is enough gravity and the universe starts to collapse in on itself, would life forms that live during this phase of the universe get younger as time passes and they would need to expend energy to stay old?

Does the phase between electric and magnetic waves of light change if the path is bent by gravity?

I have a complex signal eg: cos(wt + phase1) + i*cos(wt + phase2) the frequency of both the waves is same. When i have a look at the phase spectrum of the above signal, i am not able to interpret the phase values. They are making no sense. I tried to determine phase shift for real signals and...

Hello, I'm trying to understand how can I compute a phase graph from diffraction. I will follow here Fourier transform formalism of finding the light distribution on screen after diffraction. I'm considering a 1D problem. Suppose I have a single slit of width a. This slit can be mathematically...

Homework Statement The expression for electric charge on the capacitor in the series RLC circuit is as follows: q(t)=A*exp(-Rt/2L)*cos(omega*t+phi) where omega=square_root(1/LC-R^2/4L^2) What is the phase phi, if the initial conditions are: q(t=0)=Q I(t=0)=0 Homework Equations The damped...

Homework Statement I need to determine the minimum solvent and number of stages in an extraction process. What I need to do first is drawing the phase envelope (miscibility gap curve) inside the ternary system triangle diagram. I am given the equilibrium values of A,B and S (solvent) in both...

Hi, Just made a small thought experiment on the train, haven't really thought about it in depth. I was just wondering, if I created the above scenario (open circuit secondary and a voltmeter), would I get a voltage (assuming there is a difference in turns for primary and secondary)? Neglecting...

Dear all, Interested in change phase, I would like to set a simulation to understand the multiphysics phenomena of heat storage in a shell and tube tank between hot water as the heat transfer fluid and a PCM ( phase change material) using the commercial CFD software Fluent. The purpose is to...

Hello, I'm trying to calculate a recurrence relation of the phases of 3 telescopes in a closure phase. Usually in a stellar interferometer we have 3 telescopes, located in a triangle, measuring intensity of light in 3 points on a far field plane. I found an article, describing how the phase is...

Hi so I am wondering about potential phase difference in some 110v 60 hz household wiring... Say I have two switches to control one light and am too cheap to buy 3 way switches. If I were to run power from switch 1 to switch 2 (bypassing switch 1), so that they both had power at the switch, if I...

Homework Statement Given symmetric three phase system (see attachment) of phase voltages with angular frequency \omega=100 rad/s, R=5\omega L=100\Omega. Find capacitance of capacitor C such that power factor of three phase receiver has maximum value. Homework Equations Power factor is given by...

Hello everyone. So I have been tasked with an interesting take on what seems to be a classic problem, that is, designing a PWM controller for a single phase inverter. Now, in all the books I've read this problem has two control loops, an inner current loop and an outer voltage loop. The...

Guys, I'm having a lot of issues where I work with a sewage scraper bridge chattering it's drive contactors when being called to run, the coils for the contactors are switched on their neutrals from an Allen Bradley logix processor. The control circuit is 24v AC. I've spent a few hours on this...

If I have something like: $$\lvert \langle M \lvert \hat{L}_x+i\hat{L}_y \rvert M-1 \rangle \rvert ^2=c$$. where ##c## is any old real number. If I undid the modulus square to find: $$ \langle M \lvert \hat{L}_x+i\hat{L}_y \rvert M-1 \rangle=\pm \sqrt{c} $$ Would I not have to consider...

Homework Statement Assume a particle with a wave function ##\psi(x)## such that ##-\infty < x < \infty##, that move under some potential ##V(x)##. Show that: a) two wave functions with same energies can only differ by a complex phase; b) if the potential is real, then you can choose the wave...

If you produce three massive particles with m1=/=m2=/=m3 near threshold (beta -> 0), the cross section of the production is supressed by a factor beta^4, where beta = sqrt(1-(M_tot)^2/s) and s is COM energy. I have been trying to prove this statement, but I can't seem to manage. Could anybody...

Homework Statement "design a band pass circuit having a midband gain of 20 dB with -3 dB frequencies at 20 Hz and 20 KHz the amplifier should not produce any phase shift." does midband gain strictly apply to voltage gain (because that's how i look at it)? I was going to use a common collector...

Homework Statement The figure shows the displacement y versus time t of the point on a string at x = 0, as a wave passes through that point. The scale of the x axis is set by ys = 84.0 mm.The wave has form y(x, t) = ym sin (kx - ωt+φ). What is φ? (Caution: A calculator does not always give the...

Hello everyone, I am beginner in fluent v15, and I want to simulate the temperature change as a function of time in the phase change materials "PCM" and the heat thermal fluid "HTF" and the PCM fusion Front. Regarding the geometry I chose to work with two coaxial tubes: the inner tube contains...

three phase induction motor can have minimum two poles, so synchronous speed of the machine can be 3000rpm. While single phase motors have two windings - auxiliary and main winding, so minimum number of poles in single phase winding is 4??!...am i right?

Homework Statement Light of wavelength λ = 450 nm is incident upon two thin slits that are separated by a distance d = 25 μm. The light hits a screen L = 2.5 m from the screen. It is observed that at a point y = 2.8 mm from the central maximum the intensity of the light is I = 55 W/m2. a)...

Homework Statement Calculate the value of the wave at t = (2, 3, 4, 10) ns 0.4 cos(10^8 * t + (1/3) * y) az Homework Equations N/A The Attempt at a Solution This is the last part of a problem. I have already found the phase shift of 1/3 and wavelength of 6 pi. I have already been given the...

Hi all, I am designing a three phase 11000/433 Volts Delta/Star 50 Hertz transformer in Ansys Maxwell. It has 792 turns in 6 layers on HV side (132 turns per layer) and 18 turns in 2 layers (9 turns per layer). The resistance as I have calculated is 0.1325 ohms per phase of HV winding and 5.57...

Homework Statement A pair of die-hard sports fans decide to ride their motorcycle to the local game, equipped with identical air horns. While stuck at a stoplight, one rider blasts his horn, emmiting a coninuous sound at a frequency of 10 rads/sec. The second rider waits just the right amount...

I've came across many references for pressure drop calculations for dilute phase pneumatic conveying, but I've yet to encounter any for dense phase. Anyone has any idea how do i calculate that? Thank you

Homework Statement A 100 kVA, 2300/230V, single phase transformer has the following parameters: Rp = 0.30Ω, Rs = 0.0030Ω, Rc = 4.5 kΩ, Xp = 0.65Ω, Xs = 0.0065Ω, Xm = 1.0 kΩ The transformer delivers 75 kW at 230 V at 0.85 power factor lagging, find: a) The input current. b) The input voltage...

Homework Statement Given that the overall weight percentage of ferrite along the grain boundaries of an as-cast steel with unknown C amount is 35.23%: a) Identify if it is hypoeutectoid or hypereutectoid. b) Identify the amount of carbon alloyed in the steel. c) Identify how much ferrite and...

Will constantly randomizing the phase of an audio signal, say a speaker in the corner of a square room, reduce standing waves (i.e. room modes) in the room? For example if you wanted to create a diffuse field in a small (i.e. no standing wave interference patterns) at low frequencies.

Homework Statement The Hamiltonian for a single diatomic molecule of identical atoms is given as $$H=\dfrac{\vec{p_1}\cdot\vec{p_1}}{2m}+\dfrac{\vec{p_2}\cdot\vec{p_2}}{2m}+\dfrac{K}{2}(\vec{r_1}-\vec{r_2})\cdot(\vec{r_1}-\vec{r_2})$$. Find the grand canonical partition function for a gas of...