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...
I have got a problem:
It's well known that two electric charges have either attractive or repulsive forces on each other.
And Einstein told us that there is no message that can travel at a speed beyond c.
Besides I was told that the actions and reactions between the two charges are based on...
Homework Statement
This was a lecture that wasnt taught to us but we were given sample problems with answer but no solutions and i tried to solve some but ends up with wrong answer.. so here's the given:
a 3 phase 10kVA, 440V 60 Hz, y-connected alternator supplies the rated load at 0.8...
Homework Statement
1. A 4MVA, 13.3kV, 60Hz, 3 phase, delta-connected alternator has an effective resistance of 5.2 ohm/phase and a combined armature reactance of 54 ohm/phase. Determine the full-load generated voltage per phase, a. At unity pf, b. at 0.8 pf lagging, and at 0.866 leading pf.
2...
Homework Statement
Satellite in synchronous orbit with equator of Saturn. Find altitude in km.
rotational period = 38826 s
radius of Saturn = 6.03E7 m
mass of Saturn = 5.68E26 kg
Gravity constant = 6.673E-11
Homework Equations
T^2 = (4pi^2)(r^3)/(Gm)
The Attempt at a Solution...
I am required to design a synchronous binary counter using jk flip-flops giving the count sequence: 0, 8,9,4,7,2,1,0
I have derived the excitation table using 4 jk flip-flops, however when using karnaugh maps to minimise or trying to use the unminimised function in a circuit I am unable to...
We simulated a 200MVA synchronous -salient pole- generator, using the 2D finite-element simulation program OPERA (by Vector Fields).
We are trying to determine some parameters of the generator such as transient, subtransient and synchronous reactances as well as time constants by applying...
Hi,
Basically I'm doing a report on a logic analyser lab - I realize this isn't the homework section - and I'm looking to extend a basic discussion on synchronous/asynchronous data transmission to analysis of pumped and source-synchronous transmission...
Hi, I have a question about synchronous motors. If the DC field winding of a synchronous motor were to be replaced by a low-impedance short-circuited coil and the stator were to be supplied with 3-phase AC, would the rotor spin?
If the answer is yes, would the rotor follow the direction of...
Hi everyone
Books mention the Open Circuit and Short Circuit tests on a synchronous generator in order to determine its synchronous impedance. One observes that the Short Circuit Characteristic (plot of short circuit armature current versus field current) is a straight line all the way...
I have been toying with an SF scenario in which an Earth-like planet has a synchronous moon. Among the consequences are regular eclipses every spring and autumn, poor visibility of the stars on the side facing the moon except during eclipses, and no need for chronometers to determine your...
[SOLVED] radius of synchronous satellite from a planet
Homework Statement
A "synchronous" satellite, which always remains above the same point on a planet's equator, is put in orbit about a planet similar to Jupiter. This planet rotates once every 7.8h, has a mass of 1.8e27kg and a radius of...
Hi,
I am having trouble understanding the three light bulb method for checking whether of not two generators have the same phase sequence. It states in my book, "If all three bulbs get bright and dark together, then the systems have the same phase sequnce."
My question is, if the two...
[SOLVED] synchronous orbit
Homework Statement
A orbiting satellite stays over a certain spot on the equator of (rotating) Mercury. What is the altitude of the orbit (called a "synchronous orbit")?
The answer needs to be in km.
Homework Equations
I know the synchronous orbit is...
My problem is defined like that. I am trying to find radial and tangential field distribution on a surface of the rotor of a large airgap synchronous machine. To do that I start from the general scalar potential equation solution in polar coordinates of the form pot = (ar+b/r)sin(teta). I take...
Im a electrical engineering student.
I am now trying to understand the operation of synchronous motor.
I need helps from electrical professionals out there about the excitation system of the motor.
can someone give me a circuit diagram of the exciter?
any advice on the methods of...
Hi,
First, I'll note that this is not a homework or project question - I'm studying for a test, and am trying to better understand the material.
Note: I don't think that I'll need to know how to do up/down counters, although if you feel like explaining those, or pointing me in the right...
Homework Statement
(Problem 226) Design a Moore type synchronous state machine with only two
states, two external inputs X1 and X2, and one output Z. When X1 X2 = 1 at the
next clock timing event, output Z goes to 1. Output Z then goes to 0 unless X2 = 1
causing the output to stay at 1. Use...
Homework Statement
(Problem 225) Design a synchronous circuit using negative edge-triggered D
flip- flops that provides an output signal Z which has one-fifth the frequency of the clock
signal. Draw a timing diagram to indicate the exact relationship between the clock
signal and the output...
Homework Statement
(Problem 205) Design a synchronous counter that has a Moore output decimal
sequence of 0, 1, 3, 5, 7, and then repeats this same sequence over and over. To
ensure illegal state recovery, force all unused or illegal states to go to 0. Carry out
the design using positive...
http://palantir.swarthmore.edu/maxwell/courses/e015/F06/labs/lab01/74191.pdf
I have this IC with me, and I have to draw the timing diagrams. I'm doing good so far, except that during the middle of a clock pulse, the U(not)/D changes from 0 to 1 (counting up to down). It happens dead in the...
I'v been trying to work out this question for ages, but nothings quite working for me, here goes..
q. a) calculate the orbital radius of a synchronous satellite (one period of 24hr, so appears stationary above anyone point). Approximately how many radii of Earth is this orbital radius? Why...
Hey, I have some problems with my synchronous counter. Here is what I got. sorry for the big and bad quality of the pic. My scanner sucks :(
Here's the karnaugh map. I need to simplify them and use only NAND and inverters if needed.
http://img101.imageshack.us/img101/7335/hw4na.jpg
I need to...
Hi everyone. There are 2 questions i cannot solve here. So i am hoping someone here can help me out. Here are questions:
(1) Design a synchronous counter using J-K flip flops which will count
through the sequence 0, 2, 4, 6, 8, 10, 12, 14, 0.
(2) Design a synchronous down counter using...
Hello, I'm a little confused about synchronous machines. Specifically, I don't understand how the armature coils are wound. In discussing how the windings are configured in a three-phase synchronous machine, my textbook provides several diagrams which suggest that the windings of a coil go...
A rocket is used to place a synchronous satellite in orbit about the earth. What is the speed of the satellite in orbit?
I know that G= 6.67x10^-11 and the Mass of Earth is 5.98x10^24 kg.
So I'm to assume that I use the equation
v= Square root of([G*M]/radius)
But I don't know how...
Venus has a rotational period of 243 days. What would be the altitude of a syncom satellite for this planet?
I am pretty sure a syncom satellite is a satellite that orbits synchronously to the rotation of the planet.
I don't know how to solve this problem... help
I'm supposed to build a 4 bit synchronous up counter that counts in binary from 1-12 and restarts. I've made a circuit similar to the image shown below. My question is, what do i do to make it count from 1-12 instead of 1-16 and restart back at one...
I am trying to develop a circuit to convert 5-18Vdc, 100ma max to 0.4Vdc, 400ma. I am working on a synchronous buck converter design but I am finding limited resources on a discrete design. All of the buck converter IC's I found do not go low enough and have inadequate efficiency when they are...
I have been studying Linear Synchronous Motor (LSM) technology recently and there is one thing that has me boggled.
I read that the velocity of anything using LSM depends on the frequency of the current being applied to the coils. The equation I have seen is-
v = 2fLw where "f"...