TRC-2019 Presentation 34:48 Minutes

by Trent Martz, IVC

Torsional transmission issues can often be the cause of mechanical failures in rotating equipment. Torsional related failures can be caused by excessive peak torque loads and torsional resonances. Monitoring the motor current does not provide an accurate measurement of the actual torque on the drive components. This is particularly true during transient events or through complex drivetrains. Torsional issues are also often difficult to detect using standard NDT methods such as vibration analysis and may be the cause of many of the “mysterious” repeat and often chronic drive component failures. A direct measurement of the torque on the shaft using strain gages is the only accurate technique to properly assess the torsional conditions.

An analysis will be made of why motor current and vibration are not the best methods to accurately measure torque. Several examples will be illustrated with actual field acquired data comparing measured torque to motor current and vibration measurements. A discussion of strain gage based torque telemetry measurements and their proper implementation will take place. The discussion will cover strain gage theory, implementation for torque measurements, and options for different types of telemetry systems.