A Brazilian gearbox manufacturer had a mystery to solve in the giant drive system of a Brazilian sugar cane processing mill. The coupling at the gearbox is a special “overload coupling” and it broke repeatedly during the routine sugar mill process. The special coupling has a mechanical torque limiter to prevent overload, but the limiter never activated. The gearbox itself was not damaged.

Trying to find the cause of the broken couplings, the gearbox manufacturer called in our Brazilian agent, Torkflex Transmissões Industriais Ltda, who installed the TorqueTrak 10K telemetry instrument plus Op-Torq FIELD TEST 2 data acquisition system to measure and analyze the true mechanical load of the sugar milling process. Look closely at these photo and you will see the torque pattern strain gage plus TorqueTrak 10K Transmitter and 9V Battery installed on the giant rotating shaft.

They expected to find high torque spikes in the milling process, high enough to break the couplings. But to their surprise, they found no torque spikes. In fact, there were no overloads at all. The process load proved to be well within design limits. This interesting discovery prompted the gearbox manufacturer to contact the manufacturer of the special “overload coupling”, who then performed some tests and found the problem to be the coupling material itself. In the end, everybody was satisfied that they had correctly diagnosed the problem and implemented a corrective action that would prevent it from happening again.