SKF CMSS6165, Руководство пользователя

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Applications
Using the Stroboscope to Measure RPM
5 - 2 Strobe Light
User Manual
For example, when viewing a shaft with a single key
way you will see one stationary image of the key way
at the actual speed and at 1/2, 1/3, 1/4, etc., of the
actual speed. You will see 2 images of the key way at
2 times the actual speed, 3 key ways at 3 times, etc.
The Flashes Per Minute (FPM) equals the shaft’s
Revolutions Per Minute (RPM) at the highest flash
rate that gives only one stationary image of the key
way.
Example: Object Rotating at 5,000 RPM
If the speed is outside the full scale range of the
stroboscope (50,000 FPM), it can be measured using
the method of harmonics and multipoint calculation.
Start at the highest flash rate and adjust the flash rate
down. You will encounter multiple images so be
aware of these. Note the flash rate of the first single
image you encounter, call this speed “A”. Continue
decreasing the flash rate until you encounter a second
single image. Note this speed as “B”. Continue
decreasing the speed until you reach a third single
image at speed “C”.
For a two point calculation the actual speed is given
by:
RPM = AB/(A-B)
For a three point calculation:
RPM = 2XY(X+Y)/(X-Y)2 where
X = (A-B) and
Y = (B-C)
Stopped Image 1/3 times 1/2 times 1 time 2 times 3 times 4 times
Flash Rate (FPM) 1250 2500 5000 10000 15000 20000