greetings, I am building a small wind turbine for a project. I bought this generator http://www.amazon.com/gp/product/B000AAYBV4/ref=ox_ya_os_product

I was curious on how i could use my oscilloscope to measure the rpm at certain output voltages. Thanks.

I will post pics when I am all done

 

Does it output DC or AC voltage?

 

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

 

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.

 

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

Yes except that you may have to divide by the number of poles on the generator.

 

Does it output DC or AC voltage?

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

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

will try this weekend

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.

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

Yes except that you may have to divide by the number of poles on the generator.

noted. thanks


will report back with what i find this weekend

 

I am able to get a reading on AC

Unless your multimeter is very sophisticated it reads average on AC. This can be seriously misleading on waveforms very different from sinusoids.

 

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