Strain Gage Accuracy

Measuring torque in a rotating shaft can be done in a variety of ways. Riverhawk has been producing a strain gage based torque measuring system since the late 1970’s (formerly known as Indikon). Strain gages remain the most accurate and direct way to measure strain in a shaft.

Manufacturers of other devices typically use phase shift technology that measures twist across an entire coupling from flange to flange. Over the years, these companies have tried to convince users that the strain gage technology is unreliable.

Riverhawk Torque Meters

Strain gages do fatigue just like any other material. And just like any other material, they will not fatigue if used within the endurance limit of the material. Riverhawk Torque Meters are the only ruggedized strain gage based torque measuring devices that have over 30 years in service with the original strain gages. We work with all major coupling manufacturers to make slight modifications to the coupling spacer tube that limit the strain to well below the endurance limit of the strain gage. We have also developed proprietary mounting and protection techniques that ensure the strain gage will provide reliable output for the life of the coupling.

Benefits of Strain Gage Riverhawk Torque Meters

There are several benefits to a Riverhawk strain gage based torque meter system….

• Strain gage based torque meters cost less as they require less modification to the coupling and the coupling guard.
• Strain gage based torque meters can measure torque at zero speed. Phase shift torque meters require a minimal rotation speed and may require speed compensation, which introduces additional potential sources of error.
• Strain gage based torque meters add far less weight to the coupling with a lower overhung load or moment.
• All Riverhawk Torque Meters include two complete calibrated systems for redundancy in the event of malfunction.
• Movement or location of mechanical parts does not affect accuracy of the torque measurement
• New additional dynamic torque option for instantaneous measurement, torsional vibrations, and start or peak torques.

Riverhawk Strain Gage System Upgrades

Riverhawk recently performed an upgrade on a system that was over 20 years old. The old analog electronics were re-vamped and upgraded. The strain gages themselves were left un-disturbed as originally mounted. We simply upgraded to the newer digital electronics package and factory calibrated the system to an accuracy of .25% traceable to NIST standards.

If you have an application and have design questions, our Technical Support Team would be glad to help. Our design engineers have hands on experience with torque measurement systems and can help in several ways. Please contact me, Rick Donegan, if you have product questions or would like additional information on our torque measurement systems.