Extech Instruments 461825 Stroller User Manual


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3 461825-EU-EN v1.6 10/13
Operation
STROBOSCOPE MEASUREMENT PROCEDURE
Select the Stroboscope Function and Range using the Range/Function Select Switch. The switch
has four positions, three of which are stroboscope-dedicated with white range numbers. The fourth
position is Photo-Tachometer dedicated and is labeled as such.
Speed Measurements.
1. Remove power to the moving object under test and affix a target mark on the area to be
measured.
2. Apply power to the moving object and press the stroboscope's Measure Trigger Button.
3. Aim the Stroboscope light beam toward the marked area on the object under test.
4. Use the FINE and COARSE adjust knobs to synchronize or "stop" the motion of the object's
mark. A single stationary image of the mark provides actual speed measurement data.
NOTE: Care must be taken to ensure that the mark is providing a 1:1 measurement. This is done
by checking that there is only one mark and not two, four, or more stationary marks on the object
under test. Two or more stopped marks indicate "harmonic" measurements (2:1, 3:1, 4;1 etc.)
which provide a doubling, tripling, or quadrupling of the actual speed. A useful method of avoiding
harmonic measurements is to adjust the FINE/COARSE knobs until two images (marks) appear
and then lower the flash rate (via COARSE/FINE knobs) until a single, stationary image appears.
This is the actual speed.
Inspecting a moving object
Measure the speed of a moving object as described above and move the FINE adjust knob
alternately higher and lower to visually inspect all areas of the device.
PHOTO-TACHOMETER MEASUREMENT PROCEDURE
1. Select the Photo-Tachometer function by moving the Range/Function select switch to the
PHOTO position.
2. Affix a small piece (approx. 0.5") of supplied reflective tape to the object under test.
3. Press the meter's Measurement Trigger button and align the Photo-Tachometer light
source with the reflective tape mark on the moving object.
4. Wait until the Monitor Indicator appears in the upper left hand corner of the LCD
indicating that synchronization has occurred.
5. Release the Measure Trigger button only after the reading has stabilized (approx. 2
seconds).
NOTE: To obtain better accuracy for low RPM measurements (less than 50 RPM) use more than
one piece of reflective tape. Divide the meter reading by the number of reflective tape pieces for
accurate measurement data.
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