Need info on low speed rotational transducers

How about a stopwatch and clipboard+pad+pencil to time rotations and record the data?

It would help if you were more specific -- speed and application.

Dear Jeff

Thanks for the reply. I need info on low speed rotational velocity transducers in the range less than 10 RPM.

The analog output type (0-10 V or 4-20 mA) would be fine.

Sina

One group that likes photoelectric non contact tachometers is the airplane homebuilder movement. They stick a reflective tape on a prop (or shaft) and read off RPM.

Not too expensive

Brian Whatcott Altus OK

The 10 rpm part is easy. Just measure the rate of change of a position transducer, or measure the pulse rate from an incremental encoder.

Ranging down to ... what? is the hard part.

The OP should also be aware that specialized 'zero speed switches' exist for detecting the _absence_ of rotation, which may be his actual concern.

-Mike-