TB 9-6680-286-35
8. RPM
a. Performance Check
(1) Select a minimum of four evenly spaced calibration speeds over the range of the
TI being calibrated, up to 90% of full TI range (limited to 10,000 RPM on TI high range (see
one speed on each remaining range.
(2) Select tachometer calibrator CW direction and ensure the STOP control is activated.
(3) Holding TI in horizontal position, insert tip into hole drive of tachometer
calibrator, utilizing any adapters as required by TI.
(4) Set tachometer calibrator display select switch as necessary (1X or 2X) to
achieve desired RPM speed.
(5) Press tachometer calibrator START control and adjust SPEED control for a TI
indication of the first speed selected in (1) above.
(6) The tachometer calibrator display indication will be within the applicable
specification listed in table 1.
(7) Repeat (4) through (6) above for each remaining range and speed selected in (1)
above. If TI reads in both directions, check both CW and CCW directions.
b. Adjustments. No adjustments can be made.
9. Final Procedure
a. Deenergize and disconnect all equipment.
b. Annotate and affix DA label/form in accordance with TB 750-25.
