What is Synchronous: Definition and 134 Discussions
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or in time. Systems that operate with all parts in synchrony are said to be synchronous or in sync—and those that are not are asynchronous.
Today, time synchronization can occur between systems around the world through satellite navigation signals.
I'm reviewing some subjects that I long forgot and now I'm studying synchronous machines.
So, when you change the field current (of the rotor) of s synchronous generator, the result is a change in the magnetic flux, which change the internal voltage (Ea). That will result in a change in the...
[Moderator's note: Spun off from previous thread due to topic shift.]
I believe this is only possible if the set of timelike curves forms a congruence that is both geodesic and hypersurface orthogonal. (The congruence of worldlines at rest in a global inertial frame in Minkowski spacetime of...
Hello everyone,
I'm sorry if this is not the right sub-forum to post this, but this doubt has been haunting me for a while.
I've got some rotatory machine -let's say, generic synchronous machine-. Turns out there are typical values for [kg m^2] (inertia) in the 2-10 range; the software I'm...
Hi,
reading the Landau book 'The Classical theory of Field - vol 2' a doubt arised to me about the definition of synchronous reference system (a.k.a. synchronous coordinate chart).
Consider a generic spacetime endowed with a metric ##g_{ab}## and take the (unique) covariant derivative operator...
For a synchronous buck converter, does soft switching have to be implemented? I assume there will be some ringing if not. If soft switching is required/recommended, can it be implemented on just one of the switches to simplify control and still have most of the benefit?
The question is regarding an electrically excited synchronous generator.
Consider that this generator is not connected to the grid and thus not locked with the grid frequency.
This generator is spinning at variable speed and gets constant and similar excitation current
meaning that the...
I want to understand the parameters of the synchronous motor
Rated Power -> This is the maximum power the motor can deliver -> Is it correct? I can operate the motor for any power less than this?
Rated Torque -> This is the maximum torque beyond which the motor cannot produce?
Rated speed ->...
Generator - 1800rpm, 11kV, 656A. While running Gen, a large load was turned on, and excitation voltage went from 23V to 120V, but that's a normal situation that happens every time and on all Generators. But this time after turning on the large load, vibrations started increasing, and Gen tripped...
It is pretty well known among electrical machines folk that large, salient pole electrical machines start typically with the field winding shorted and starting torque developed by current induced in the damper windings, acting much like a squirrel cage induction machine. The net machine torque...
Why is that?
It's easy to understand how planets and moons can become tidally locked.
but why do weird things like 3:5 Jupiter/Saturn stuff happen?
Or doesn't it?
greetings.
I designed a system on simulink.
it is missing a pmsm.
I found a block on simpowersystems in simulink nde matlab.
I hope that this engine provides a nominal power of 96kw and maximum of 100kw.
so how to test it? to verify that this engine can deliver these two powers?
cordially. said.
Hi,
It has been a long time since I studied synchronous machines and I am trying to understand the mechanism of how the armature excitation can result in the generator being lagging or leading. So please correct me if I say something like it's axiomatic but its really erroneous.
Now, according...
Is it true that AC synchronous motors (the ones with the DC slip rings and excitation current running into rotor poles) have a power factor of 1.0 when they run in synchronous mode?
Would that be because with sufficient rotor DC current he rotating AC magnetic field is precisely counterbalanced...
Homework Statement
I read in my notes that "The physical size of a synchronous generator of a particular rating is larger than one of a lower rating"
Why is this so ?
The Attempt at a Solution
Is it because a larger one would be able to supply more power and therefore the rating would be higher ?
Hi All. I'm having trouble working out the solution to this problem.
A Synchronous motor is coupled to a DC Compound Motor.
The DC Machine is rated for 220 V DC. Its Armature Resistance is 1.0 Ω .
The Synchronous Machine is a 4 pole 400 V 50 Hz 3 Phase AC Machine with an efficiency of 80%...
Homework Statement
Can we use a 3 phase delta supply to a 3 phase synchronous motor who's stator windings are connected in star (wye)?
The Attempt at a Solution
I was thinking no, since I read in my notes that the rotor has to be supplied with a "continuous current"
But I'm not sure. I have...
Homework Statement
Two 3-phase 60-hertz 35-kilovolt synchronous generators (G1 and G2) each have synchronous reactances of j9 ohms per phase with negligible armature resistance. They are connected in parallel to supply a 36-megawatt load at rated voltage and power factor of 0.90 lagging...
In electrical machinery and power systems, the synchronous reactance is treated as a constant reactance in series with the generated emf and is independent of load condition. These threads were very helpful for me in understanding this concept (thanks to @jim hardy!)...
Hi
I know that when studying fault conditions for synchronous machines you have three reactances: Sub, transient and steady state reactance. Where the magnitude of the reactances are (from smallest to largest) in the same order as previously listed.
However, I have tried searching - hoping to...
Hi,
In an AC 3-phase induction motor (i.e. asynchronous motor) rotating magnetic field is produced by the stator and in this case rotor consists of simple cage having metallic bars or with coils wound around the rotor. The rotating magnetic field magnetizes the rotor and attracts it. As the...
< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown >
Here's a question from a national-level engineering exam in India called GATE (2017).
It is for 2 marks, numerical answer type.
Two synchronous motors A and B in parallel with identical O.C...
Hello everyone
Im new on the forum and I just discovered what are sync machines...
I have really basic question what I still cannot figure out.. I did some experiments with motor for different field currents and torques. In the result I measured armature currents and did V curves. But next...
Hi,
I'm trying to do a very simple analysis on Simulink where I am applying a speed to a Permanent Magnet Synchronous Generator with a purely resistive load.
I'm not familiar with PMSGs so the results I'm getting don't really make any sense to me. Could anyone go through some simple design...
Homework Statement
In order for the enterprise to use its transporter it must be in synchronous orbit over the beam-down point. What heigh above the planet Mars must the enterprise be for a synchronous orbit?
Homework Equations
Please, can someone tell me for future reference what I should use...
Homework Statement
I am trying to design a 5-bit sequence recognizer. The circuit has to detect two sequences of bits. The first sequence is 11001. The second is 10010. The output when no sequence should be 00. When the 1st input sequence is detected, the output should be 01. When the second...
Homework Statement
A star-connected, three-phase synchronous induction motor takes a current of 10 amps from a 415 volt supply at unity power factor when supplying a steady load. If the synchronous reactance is 5 ohms/phase and the resistance is negligible, draw the phasor diagram and...
Hi All
I have a standard induction motor torque vs. synchronous speed diagram and I want to calculate the shaft-speed at any point along the curve (from 0% synchronous speed to 100% synchronous speed). I know that the synchronous speed is 1500 rpm at 95% synchronous speed (which is also at...
It's not really a problem but I was studying Sync Motors for assignment and didn't understand few things.
1. Homework Statement
http://s1320.photobucket.com/user/ajaytulsiani/media/-%20ia_zps8oujbzrh.jpg.html http://s1320.photobucket.com/user/ajaytulsiani/media/synch_zps3bry0aah.jpg.html
In...
Hi,
I was wondering if some kind soul could explain to me why salient pole machines are preffered in hydropower? From what I've read salient pole machines are preffered for applications with "low" rpm, while non-salient poles are used for applications that runs at higher rpm. O
What is the...
A synchronous generator is connected to the grid through a reactane of j0.65 pu. The grid voltage is 1 pu and the generator is feeding 0.7+j0.6 pu power to the grid. After some calculations, the generated emf is found to be 1.46 ∠18.12° pu. If the active power is increased such that new complex...
I am Telecommunication student but interested in motors.Especially, power generators.I was wondering why permanent magnets are not used in synchronous motor's stator or rotor? Is induction motor more efficient than permanent magnet used motor?
What about in power plant generators, do they use...
Homework Statement
"Design a Synchronous Counter Mod-12 Up/Down, using only Flip-Flop Type D. A binary input ##U## that determines if the counter has to increase (##U = 1##) or decrease (##U = 0##).
Homework Equations
Flip-Flop Type D equation is
##Q_{t + 1} = D##
The Attempt at a Solution
I...
1. Problem Statement:
A 4-pole, star-connected, 50 Hz, 11kV, 40 MVA turbogenerator, with a synchronous reactance of 0.8 p.i., is connected to a power network. This power network can be represented by 11-kV infinite bus with a series reactance of j 0.5 Ω. A voltage regulator adjusts the field...
Hi I would ask someone that is pratical with Simulink in particular of Simscape about a problem which involve my simulation in Matlab-Simulink of a permanent magnet synchronous machine that is connected, by a rectifier, to a DC current source.
all the blocks of the simuation are included into...
Sorry for bad title(little informative regarding my question), however I came across the following question given as an exam question at some university.
Question:
"A synchronous generator is running overexcited with excitation voltage Ef = 1.40 p.u and connected to the network at voltage of 1...
Homework Statement
The Attempt at a Solution
First up, part a.
The first one is really simple. The generator is working at its rated voltage of 13.8kV, right? So, would the required field current not be just 225 Amps?
Next, part b.
To sort of explain what's going on, I first found the...
Hi everyone!
As a Belgian student electrical engineering, I am going to Peru this summer with Humasol vzw, a development organisation that works with engineering students. Our job is to build a hydro turbine next to a small river to provide a little community with electricity. Also part of our...
Hi
I was wondering if someone could help me understand and explain to me how one can control the frequency of the grid from help of the active power (frequency -> power angle -> active power) and how reactive power can be used to control the voltage level.
My thoughts:
Voltage Control:
I don't...
Homework Statement
The armature resistance per phase is given as 24.7ohms.
Delta configured machine.
Open circuit voltage is 220v, short circuit current is 1.1A at 3000rpm.
Rpm is dropped to 1500rpm and no load line voltage is 100.
Find power and efficiency if an inductive load of 1.4H is...
Homework Statement
Explain how the synchronous machine stator current can be varied if the load is constant. Justify your answer with phasor diagrams.
2. The attempt at a solution
If load is constant then load angle, the angle between induced e.m.f. and terminal voltage remains the same...
Homework Statement
I studied that a larger air gap in alternators aids in sinusoidal mmf distribution ..I didn't get this as larger air gap should deteriorate the wave..but here it is opposite..?? Is it right ?? [/B]Homework EquationsThe Attempt at a Solution
One point can be said that larger...