Back to results
US 4,225,851 AGranted
Self-calibrated subcarrier telemetry system
AssigneeGeneral Electric Company
InventorsJohn M. Reschovsky, Walter Whipple, III
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeGeneral Electric Company
InventorsJohn M. Reschovsky, Walter Whipple, III
Estimating the term…
A self-calibrating subcarrier telemetry system for measuring strain on rotating members of a turbine under operating conditions. A rotor mounted portion of the system includes a strain gage transducer bridge excited by a subcarrier alternating current derived from an induced power source. The transducer bridge produces an output signal, amplitude modulated by the strain signal whereby the modulation shifts the strain signal into a higher frequency portion of the spectrum away from low-frequency noise related to the rotational speed of the turbine. A calibration signal is introduced by automatically unbalancing the bridge transducer periodically at a rate related to the subcarrier frequency. The strain signal is recovered in a stationary data reception portion of the system by a synchronous detector. A reference calibration signal is provided against which receiver gain is adjusted to achieve a null, leaving only the calibrated strain signal and achieving indpendence of variations in system gain. Nulling against the unipolar calibration reference further provides a means to distinguish tensile and compressive strain.
In combination with apparatus having a stationary member, and a heavy rotational member or rotor adapted to rotate at high speed within said stationary member, a telemetry system for detecting strain on a part of said rotational member comprising:
Dependencies are inferred from the claim text.