oscilloscope to measure RPM?

Discussion in 'The Projects Forum' started by 03GTS, Jun 2, 2009.

  1. 03GTS

    Thread Starter Member

    Jan 5, 2007
    12
    0
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Does it output DC or AC voltage?
     
  3. Externet

    AAC Fanatic!

    Nov 29, 2005
    763
    57
    With your generator running at a somewhat steady speed, connect the oscilloscope to its output and if there is any repetitive waveform or spike, you can discern its period on the oscilloscope.
    Turns per second = frequency = 1 / period. If you want turns per minute instead of per second, multiply by 60.
    Miguel
     
  4. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    2,040
    287
    If you have a photocell or photoresistor you could aim at the blades (assuming you have some daylight) you might get enough of a reflection to see on a scope.
     
  5. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Yes except that you may have to divide by the number of poles on the generator.
     
  6. 03GTS

    Thread Starter Member

    Jan 5, 2007
    12
    0
    looks ac just by hooking up my multimeter to it. it reads 0 volts on DC. I am able to get a reading on AC

    will try this weekend

    i dont. but will remember this for future reference thank you


    noted. thanks


    will report back with what i find this weekend :)
     
  7. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Unless your multimeter is very sophisticated it reads average on AC. This can be seriously misleading on waveforms very different from sinusoids.
     
  8. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    If it is AC, use the scope to measure its frequency and then calculate the angular velocity by using:

    ω=2*pi*f

    If you want rpm=ω*60/2pi
     
Loading...