A tachometer — Accelerometer — Vibrometer for instrument-gyroscope testing

This paper gives an account of the development, operating principles, and use of a possibly unique instrument that has been and is of considerable value on instrument-gyroscope manufacturing and repair production lines. It is used to indicate gyroscope-rotor speed when the rotor is brought up to 1,000 rpm for bearing adjustment. Then, by the turn of a switch, the instrument indicates the rate of deceleration as the bearing is adjusted, thus permitting accurate adjustment of bearing pressures. A third position of the same selector switch gives tachometer operation up to 15,000 rpm for vibration tests. Excessive vibration is indicated visibly and audibly through another amplifier, independently of the selector-switch position.