Synchronous Definition and 127 Threads

How is synchronous reactance for a cable defined?

Hi, So when you over-excite the rotor of a synchronous motor, or under-excite the rotor of a synchronous generator, how is the flux actually changing the power factor of the armature to leading? (something to do with the magnitude of the armature reaction flux vector?) That is to ask: by what...

Homework Statement Is there no residual magnetism in case of synchronous machines? Actually I had this doubt because of the OCC of alternator as when the field current is zero the generated value of the machine is also zero unlike the dc machines..why is it so?? Homework EquationsThe Attempt...

Hi, So we're doing this Lab on Transient reactance of a synch generator and I'm reading Sarma's classic: Electric Machines Steady-state theory and Dynamic performance p. 474-479 But I can't see how to get the actual exponential time constants for the sub-transient and transient reactances? Thanks

Kind of long winded, but I would appreciate a second veiw on untangling EA's thinking about this. § 2. On the Relativity of Lengths and Times We imagine further that at the two ends A and B of the rod, clocks are placed which synchronize with the clocks of the stationary system, that is to say...

EDIT: SOLVED I designed a bi-directional synchronous counter with the sequence 7 4 6 5 2 1. The up count counts correctly (ie 7 4 6 5 2 1) but when I flick the switch to reverse it it counts backwards correctly initially until it reaches 5, and then it goes back to 2 and then back to 5 and...

What is the exact procedure for finding regulation of a synchronous generator by direct loading? We have it in our syllabus..For full load,I know the initial steps till the rated voltage is obtained at rated speed on no load. But when the load is switched on, my book says: 1.Terminal voltage...

I recently read about synchronous generator and some things really confuse me.. How does the excitation affect reactive power? I don't understand their relation.. For constant load and variable excitation, how does the power factor change? Icosø remains the same but both I and cosø change with...

I understand that one can always construct a set Synchronous coordinates (or Gaussian normal coordinates) on a neighborhood of a point in spacetime. My question is: Does one can construct a metric with only $g_{0i}=0$ such that $dS^2=g_{00}dt^2 + g_{ij}dx^{i} dx^{j}$ (where $i=1,,,,D$ and...

synchronous machine can run at synchronous speed but why can't induction machine run at synchronous speed?

in a parallel operation of synchronous generators...while synchronising a new generator to a bus..why the speed of incoming generator should be slightly more than the other generators that are connected to the bus?

Why are synchronous motors reactance grounded and not resistance grounded like in alternators?

Hi everyone, I am trying to implement the current control (Id, Iq) of a four pole PM synchronous motor. I am having trouble in making the Iq current follow a set reference. I had also implemented a cascaded speed control for a dc motor. In that case, I adjusted the gains of the PI...

Will the Earth's rotation someday be synchronized with its revolution around the Sun (one rotation on the axis per revolution), such as the Moon around the Earth? If not, why?

Homework Statement What is the closest celestial object that has bound synchronous rotation with another object? Homework Equations - The Attempt at a Solution I am almost sure it's Moon.

Hi all, This particular query is purely theoretical. Assume a standalone synchronous generator feeding power to a single induction machine (the only connected load) which is made to run as induction generator at super-synchronous speed. What will be the prevailing electrical conditions in such...

Hi all, Just a quick question about control of axial flux synchronous machine. Does it follow more or less the same technique ( which include PWM, inverter and dq transformation )? Is there any major difference from control of radial flux machine? Thanks in advance. Regards.

I am troubleshooting a 1967 GE synchronous motor used to run a reciprocating compressor. It is a 1000 HP machine. I am trying to figure out the size and purpose of the capacitor connected to the DC field. Is it there to absorb voltage fluctuations? The capacitor has burnt up and can't be...

I am reading from grainger about transient stability. I know this will be a amateur question, but... It says that when a prime mover is turning a synchronous machine, there is a equal and opposite counter torque (electrical counter torque) when the machine rotates at synchronous speed...

Hey all, If we are given a synchronous generator with the following nameplate values 10MVA, 13.8kV, 2 pole, 60 Hz why is it not sufficient to go S_{RATED}=I_{RATED}V_{RATED} as we did for transformers? My reason for asking is because I am trying to determine the voltage regulation of a...

I want a closed loop MATLAB simulation for a case study in power grid control: I'm planning to regulate the terminal voltage of a synchronous generator on overloading, by measuring the terminal voltage instantaneously, giving it to a rectifier and feeding the DC signal to the exciter (instead of...

Let's say we have small hydropower plant which can operate in on-grid and in islanded mode too. I understand a principles of frequency and active power control in a case we have synchronous generator, but what would be diff in a case of Asynchronous generator? How do we controll frequency in a...

Given a specific metric, is there a easy way to transform it in Synchronous coordinates? For example having dsigma2 = (1+z)^2 dt^2 - ds^2 - s^2 dphi^2 - dz^2 , I was able to do some substitutions, but I had to stop at the differential equations presented in the attachement.

This was a theoretical / rhetorical question posed by the professor during class. He hinted that this will be on the next quiz. I think I know the answer, but can you guys verify it for me? Homework Statement Why do we not perform the Open Circuit Test and Short Circuit Test one after...

Hi , Hope someone could offer me a solution to this piece of code, the code below shows a period in time of a synchronous generator transient response, My scaling is the problem as I am not getting 50 Hz 230 volts, your help would be appreciated.. My efforts so far are % Transient...

conflict: why synchronous machine doesn't produce induced EMF in the DC field wires Isn't it current path through winding which produce magnetic field (rotating) the must produce EMF in the dc winding of field (same theory of induction) but why isn't true in synchronous

need lectures of good references of AC synchronous and links if you have ... and I wonder why the field of it is DC ?

Homework Statement I am working on a 16:4 MUX that is comprised of four cascaded 4:1 MUXs. Each MUX has an active-low enable pin. To enable one MUX at a time, I need to use a counter that outputs the following: Clock Cycle 1: 1110 Clock Cycle 2: 1101 Clock Cycle 3: 1011 Clock Cycle...

I need to make a synchronous demodulator using basic components (op-amps, etc...) and I was wondering if anyone has currently made one. I want to avoid using an custom IC chip unless there is one available. I was looking into the Analog's AD630 and TI's INA143 (which they claim can be used as...

Hi guys. I'm wondering if someone could explain why when trying to make a 3 bit up/down counter using T flip flops, there are two and gates connected to the final multiplexer ? Can someone explain how you approach this? And same with the JK Flip flop but with an xor gate. I'm really...

Homework Statement Design and implement a synchronous 3-bit up/down counter with the following decimal code sequence: 0,1,3,5,7,6,4,2,0,… The counter should count “up” when an UP/DOWN control input Y is 1, and count “down” when the control input is 0. Counting “up” decimal...

Homework Statement Synchronous demodulate x(t). Homework Equations xc(t) = cos(2pi*fc*t), fc is the carrier frequency xm(t) = cos(2pi*fm*t), fm is the modulation frequency x(t) = xc(t)*(1+m*xm(t)), m is the modulation index m = .8 fc = 2000 hz fm = 200 hz The Attempt at a Solution I...

So I decided to take a brake from electronics, and get back to physics of synchronous machines, or alternators if you will. A great deal of help was mr. jim hardy, trying to explain the alternator in the intuitive way. And so he succeed. I got the basics right. Now I want to tackle some more...

Synchronous generator synchronous reactance Xs is composed of Xs = Xa + Xl where Xl is the armature leakage ractance can Xa is there to model the armature reactance. Although Xl is frequency dependent (Xl = Lw, where L is the leakage inductance which is constant), is Xa also frequency...

Could somebody to explain me, please, how works revers system on the one phase AC synchronous motor with two wires only. Model is 50TYZ-E and it is from small ice making machine. Where does this motor get information, that now is time to turn opposite way? Thanks in advance! Veiko

I tried simulating a simple synchronous generator driving a resistive load in isolated mode (not connected to the grid/infinite bus), using Matlab Simulink, SimPowerSystems. First I used, Input mechanical power of 1 pu, and output resistive Load of 1 Pu. And Excitation Field Voltage of 4 pu...

What will happen if the rotor speed becomes larger than the synchronous speed for induction motor?

Hi for a project i need to connect a synchronous generator to the electrical grid, i need to use 2 curcuit breakers and . How to determine the cross section of the cables required and how to connect them to the 2 curcuit breakers.

Hi, I am trying to make a digital clock using a synchronous counter. Can anyone please provide me with a proper circuit ? I am having some problems when designing it myself. Thanks.

Few questions about Synchronous generator. A rotor is rotating with angular frequency ω. In this rotor we have windings, which produce magnetic field, through a DC supply. This supply is connected to a rotor with brush contacts. Now this field induces a emf in windings, which are in...

Hello everyone. Using ListLinePlot and ListAnimate I have made an animation with a hundred frames or so. Also, I have an animated graph corresponding to that animation, plotting certain values. For my presentation, I would like to show the audience these two animations and for that reason I...

When I have the Vphase (254 V) S phase (6.2KVA) and I (24A) ? Help !

Homework Statement I'm a bit at a loss here for a particular assignment we got for one of our labs. I've been using a certain method to derive the k-maps for some circuits, but for this particular one, it didn't really work out too well for some reason. We built and implemented a 4-bit...

Hi All, I'm working on my final year project on synchronous buck converter (SBC). In this project, i have to use an adaptive gate drive (AGD) and a compensator to switch on both of the SBC switches. The AGD is connected to the second switch (Low side switch) of the converter meanwhile for the...

I'm trying to analyze the following circuit which is pretty basic. There is the circuit and it's diagram which is the solution: http://img822.imageshack.us/img822/7291/circuiti.jpg Please help me find the mistake, because my diagram becomes different from the one in the picture...

Hello everyone, I would like to ask a little help from you guys. I am designing a Permanent Magnet Synchronous Generator (PMSG) for a Wind turbine application which is of direct drive (DD) type. Being a DD type PMSG the frequency of the output is very low and hence I had to employ converter...

Homework Statement A star-connected, 3-phase, 100kVA, 415V, 50Hz synchronous motor having a synchronous reactance of 1.2ohms and negligible resistance operates at its rated terminal voltage, rated current and per-phase field-induced emf of 228V. Determine the power factor. The excitation...

Here is a multiple choice question i was completely stumped on, and still can't find the right answer for in my textbooks... Name 2 forms of excitation with respect to synchronous motors: a) under and over excitation b) dc & ac variation c) dc excitation and load variation d) armature and...

hi all i want to know What is the difference between synchronous and asynchronous motor? thanks

Meaning just like it says. Are there any time 'shifts' within this very huge Universe? Is Time a constant same-pace dimension throughout?