On Mon, Mar 7, 2011 at 7:56 PM, Olin Lathrop wr= ote: > Andre Abelian wrote: >> There is some =A0thing I do not clearly understand about VW battle >> engine. > > What equipment does this enging go in? > >> the rotor has 4 magnets on it and the board has >> 1 hall effect sensor with none latch version so each magnet will >> control each cylinder. > > How many cylinders? =A0Rember that only half fire in any one revolution, = at > least if this is a two stroke gasoline engine. > >> lets say 8000 engine RPM > > OK. > >> I divide by 60 to get the frequency 8000/60=3D133.33 > > Where to begin. =A0First 8000 RPM is a frequency. =A0Second, 133.33 is cl= early > not a frequency since frequency has units of 1/time. You can start here by learning that RPM is not "a"? frequency, it's number of turns (2pi) per minute and corresponding frequency can be found by dividing the value to 60 which is the number of seconds in a minute. > > What you apparently mean is 133Hz. =A0Pay attention to details. =A0They m= atter. No he meant 133.33Hz obviously, frequency doesn't have to be integer. Non-integer part of the frequency can be expressed as a half-turn or ..33x2pi turns in this case. Another approach would be that f =3D c / lambda where lambda is wavelength and can be chosen arbitrarily. Pay attention to details they -really- matter. > > If the engine speed is 133Hz and it is a two-stroke engine, then each > cylinder fires at a rate of 67Hz. > >> my question is witch one is correct 133.33 or 533.33 >> my understanding is it should be 533.33 > > Again, none of these are correct as should be obvious since they aren't i= n > units of 1/time. Again, 133.33 is correct because RPM is Round/Minute, where converting this to RPM/Second will yield to "the" frequency. Nominator of the equation can also be expressed as angular velocity. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .