re: question.what is the sine wave and freqency?

Question

what is the sine wave and freqency at a given r.p.m...hear is some help,the freqency is govend by the number of poles in the alternator and the r.p.m,the rotor is the moving part with the poles on it,the poles are shaped like saw teeth say 12 in all,...the stater is the part that does not move,but gives volage and current output the windings on this are square in shape,i have always thought this is the sine wave genarated,the alternator output will be a.c voltage as the rectifying diodes will be disconected,the question applies to any car alternator

Answer 1

waveform:
A waveform is a representation of how alternating current (AC) varies with time. The most familiar AC waveform is the sine wave, which derives its name from the fact that the current or voltage varies with the sine of the elapsed time. Other common AC waveforms are the square wave, the ramp, the sawtooth wave, and the triangular wave.
The sine wave is unique in that it represents energy entirely concentrated at a single frequency. An ideal, unmodulated wireless signal has a sine waveform, with a frequency usually measured in megahertz (MHz) or gigahertz (GHz). Household utility current has a sine waveform with a frequency of 60 Hz in most countries including the United States, although in some countries it is 50 Hz.

The sine wave or sinusoid is a function that occurs often in mathematics, signal processing, alternating-current power engineering, and other fields. Its most basic form is:
y=A*Sin (ωt- φ)
which describes a wavelike function of time (t) with:

peak deviation from center = A (aka amplitude)
angular frequency ω (radians per second)
initial phase (t = 0) = −φ
φ is also referred to as a phase shift. E.g., when the initial phase is negative, the entire waveform is shifted toward future time (i.e. delayed). The amount of delay, in seconds, is φ/ω.

This wave pattern occurs often in nature, including ocean waves, sound waves, and light waves. Also, a rough sinusoidal (inverse cosine) pattern can be seen in plotting average daily temperatures for each day of the year, although the graph may resemble an inverted cosine wave.

Graphing the voltage of an alternating current gives a sine wave pattern. In fact, graphing the voltage of direct current full-wave rectification system gives an absolute value sine wave pattern, where the wave stays on the positive side of the x-axis.
For more:
http://en.wikipedia.org/wiki/Sine_wave

Answer 2

Most alternators use a three phase system, the stator will have twelve poles with opposite poles wound in series and six or twelve diodes arranged to give full wave rectification. The rotor is a single winding usually surrounded with two u shaped poles pieces configured to provide four poles. A sinewave output requires one positive and one negative excursion of voltage (or current) for each output cycle, a four pole rotor will therefore produce a frequency twice that of the shaft RPM. If the shaft is turning at 1500 RPM the polarity of the output will change 6000 times a minute giving a frequency of 3000 per minute. Frequency is normally expressed in Hertz (Hz) 1Hz being 1 cycle per second. Dividing the 3000 by sixty gives the frequency in Hz, 3000/60= 50Hz. So halve the number of poles to the rotor and multiply this by the RPM and divide the total by sixty will give you the frequency in Hz. The sinewave is not normally seen, as the rectifier diodes convert the output to DC. Generators for diesel engines often have an ancillary output to drive a tachometer but this is not a true sinewave. Current is only drawn through the diodes to charge the car battery, this loading effectively clamps the sinewave to the battery voltage. Unloaded the alternator would produce a near perfect sinewave however the clipping effect of the diodes causes a flat top to the waveform. The number of poles in the stator will determine the number of phases but will not change the frequency.

Answer 3

Looks like everyone has covered it, but a few more points.

Graphed, the area inside the the sine curve is associated with the value of its content in the case of a Sine wave this value is known as the RMS (Root Mean Square) value which is about 0.746 of the peak value.
Check the 0.746 number my memory is not perfect @ 83

The poles that shape the excitation magnetic fields are known as Inter Poles.

Answer 4

co- ordinates system use variables (letters representing numbers) x,y in a 2 dimensional (flat like paper) space to plot points. ie 2,4 is 2 across and 4 up.

if you rotate a circle at a constant speed and plot x against time you get a sine wave. if you rotate a circle at a constant speed and plot y against time you get a cosine wave (identical but 90 degrees out of phase.)

a sine wave looks like a mountain for the first 180 degrees and a crater for the remaining 180 degrees and starts and returns to 0 after a full cycle.

frequency is the amount of times that the sine wave starts and finishes so if it goes up and down 50 times then the frequency is 50 hertz .

Answer 5

it truly is amazingly poorly taught even as taught in maximum faculties I easily have considered. even as taught properly it would want to upload a good number of skill for your strikes. this is not consistently dropping on the technique it would want to be increasing reckoning on the move in touch. it truly is a way of having the full mass of the body right into a punch block or kick. The sine wave must be an complete wave a lifeless ringer for shown on your physics textual content e book not a nil.5 wave as some recommend. Google Sine wave Taekwando. seek for accepted Choi explaining on youtube. accepted Choi claims to have invented it; inspite of the indisputable fact that this is been utilized in Hawrang Do earlier for generations earlier Taekwando. practice from a impartial posture ( knees really bent) dropping down than increasing and dropping returning to a impartial posture lower back with knees really bent and also you may want to get the idea. With some practice you'll discover the position this may fit on your varieties. we were practise it for years. in no way idea a lot about it. it truly is actual counterproductive even as not performed ideal. It takes a good number of time to practice. it truly is the reason it in all likelihood isn't taught a lot. It extremely makes the most massive difference in self protection circumstances even as going hostile to a larger opponent once you want each way achievable to multiply your stress. Do it incorrect and the opposit takes position you're taking stress and speed away. a good number of controversy is led to by those who both teach it poorly or do not comprehend the aplications. Few do. I easily have really ever considered it taught personaly by 2 masters , my draw close Don Broussard, and one in each of his masters now diseased Dr. Lauber. It has not something to do with enternal martial arts. it truly is basic mechanics. those who teach it poorly or incorectly many times hotel to some mystiacal crap to hide their lack of expertise. this can provide an awsome tecknique a bum wrap.

Answer 6

since a alternator rectifies its own output to a DC output the sign wave and frequency will not matter. the car could be idling or at 5000 rpms and the output of the alternator will be the same.

Answer 7

A sine wave is just a way to show the rise and fall of ac voltage. and the frequency is how many times it reaches full positive and full negative voltages per. second