GB1335866A - Apparatus for and method of measuring the horsepower of a rotating shaft - Google Patents

Abstract

1335866 Measuring horsepower of a rotating shaft electrically TELEDYNE INDUSTRIES Inc 19 June 1971 28853/71 Heading G1N Horsepower of a rotating shaft is determined by sensing torque transmitted to the shaft and the speed of the shaft and multiplying electrically these values together. Shaft 10 connecting aircraft power plant 11 with propellor 13 is provided with spaced variable reluctance pick-ups 16, 18 producing A. C. outputs which are squared at 20, 22. If a load is put on shaft 10 a phase difference is introduced between the trains of rectangular pulses from 20, 22 proportional to the torque on the shaft. A rectangular pulse train of pulse width equal to this phase difference as derived from bistable device 24 which is triggered ON by the leading edges of pulses from one waveshaper and OFF by the leading edges from the other waveshaper, and is applied to analog gate 28 directly or via Schmitt trigger 26. Constant pulse width speed pulses from monostable multivibrator 30, triggered by pulses from one of the waveshapers, 20, 22 are integrated at 31 to produce a voltage level proportional to shaft speed which is applied to analog gate 28. The output from 28 is a pulse train of pulse width proportional to torque and height proportional to speed, the pulse areas being proportional to horsepower. Alternatively the torque pulse train may be integrated and the shaft speed pulse train used to activate the analog gate. To ensure that the pulse train from shaper 20 precedes pulse train from shaper 22 the teeth on gear 12 may be advanced ahead of the teeth on gear 14 at zero torque and the meter 34 calibrated correspondingly.