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For several years I have restored antique movie theater popcorn machines from the 1940's. I design and manufacture obsolete parts for these machines for restorers across the nation. I am currently prototyping a reproduction "popcorn stirrer flexible drive cable" and am in the process of building a stress test unit to measure and test several parameters concerning the flexible cable.
Please look at my attached drawing. I found a unique way of measuring the stress applied to the "test cable" by monitoring the force and movement of the main drive motor's "shaft end play" by using a "strain gauge". When the worm gear is turning under "no load" the motor's shaft is fully retracted and applies no force to the strain gauge. But when the worm gear is under a load it forces the motor's shaft to extend slightly and applies force to the strain gauge.
I retrofitted a fully restored popcorn machine with my test device for the purpose of establishing a known set of operating parameters. Here were my results:
1. With no popcorn or oil in the kettle I calibrated the strain gauge to measure 0 oz. of force.
2. I poured in the normal oil and popcorn mix and the readout started measuring force.
3. As the popcorn started popping the force increased and eventually displayed 15.2 oz. of force with a fully loaded and popped kettle of popcorn.
4. The test results established a maximum force of 15.2 oz. (under normal operating conditions) applied to my flexible stirrer drive cable.
Here is where I need help. Can the 15.2 oz. force measurement be used to calculate a "torque" measurement? What would be the amount of torque on my cable at full load and would I express it as PSI or another standard unit of force? Do I need more data to make the conversion (gear sizes, motor RPM, shaft size, etc.) ?
Thanks,
Mike Pruitt
Please look at my attached drawing. I found a unique way of measuring the stress applied to the "test cable" by monitoring the force and movement of the main drive motor's "shaft end play" by using a "strain gauge". When the worm gear is turning under "no load" the motor's shaft is fully retracted and applies no force to the strain gauge. But when the worm gear is under a load it forces the motor's shaft to extend slightly and applies force to the strain gauge.
I retrofitted a fully restored popcorn machine with my test device for the purpose of establishing a known set of operating parameters. Here were my results:
1. With no popcorn or oil in the kettle I calibrated the strain gauge to measure 0 oz. of force.
2. I poured in the normal oil and popcorn mix and the readout started measuring force.
3. As the popcorn started popping the force increased and eventually displayed 15.2 oz. of force with a fully loaded and popped kettle of popcorn.
4. The test results established a maximum force of 15.2 oz. (under normal operating conditions) applied to my flexible stirrer drive cable.
Here is where I need help. Can the 15.2 oz. force measurement be used to calculate a "torque" measurement? What would be the amount of torque on my cable at full load and would I express it as PSI or another standard unit of force? Do I need more data to make the conversion (gear sizes, motor RPM, shaft size, etc.) ?
Thanks,
Mike Pruitt