SHIMPO DT-900 User Manual
Page 11
8
True RPM Measurement
Shimpo Stroboscopes are DUAL function instruments that give the operator the illusion of “stopped
motion” where in actuality the equipment under observation is in a moving state. By adjusting the flash
rate, equipment in motion appears to be standing still. With a slight adjustment, movement can be viewed
in apparent slow motion, which enables the operator or observer to study the process in action. All Shimpo
Stroboscopes can also measure rotational (RPM) or reciprocating (strokes per minute) speeds with the same
high precision as with an electronic digital tachometer.
To measure true revolutions per minute (RPM):
1. “Mark” the object to be measured by either visually noting an inherent distinguishing characteristic
(such as a label, scratch, etc.) or physically marking the object with a small piece of tape, pencil mark,
etc.
2. Turn power switch on.
3. Adjust flash rate from highest Flash per minute (FPM ) downward.
4. The true RPM can be noted once the action appears frozen and the first single image of the “mark”
appears (see diagram below for further explanation).
5. To verify RPM reading, press “÷2”. A single image should appear again.