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Reasons and Signs of Failing Couplings

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Reasons and Signs of Failing Couplings

The couplings are an integral part of any power transmission system, connecting two rotating shafts to transfer rotary motion and torque. For a coupling to achieve optimum performance, it must match all required conditions and operate within its intended design limits. But when subjected to torque or misalignment, parts such as the coupling bolt may go loose or fail.

So, what are the tell-tale signs your couplings are failing, and what’s causing them? Do you need to visit a coupling  manufacturer in Australia soon?

Torque Overload

One symptom of a failing coupling system is torque overload, often appearing as contact clearance holes on the disc pack bolts, severe spreading such as in consecutive links, and buckling of the disc pack. Torque overload is typically caused by high start-up torque, electrical fault, process event, or liquid slug in the compressor.

When your couplings are experiencing torque overload, you might hear loud noises or experience imbalance and total, instantaneous failure. Failure caused by this factor can be somewhat challenging to predict.

If you think torque overload is affecting your couplings, it is best to inspect them immediately for cracks and make the necessary replacements. You should also check for sizing and review the operation history for any signs of atypical events.

Axial Misalignment

Axial misalignment may present itself as a fracture near the bolt hole. 

Symptoms may include a pulsing effect in the axial readings, fluctuated axial vibration, or increased temperature. An incorrect magnetic centre, poor initial alignment, and incorrect thermal growth often cause axial misalignment.

Axial misalignment can be prevented by checking the spacing, capacity, equipment end play, magnetic centre, and thermal growth values.

Angular Misalignment

Possible symptoms of angular misalignment may include high axial vibration, increasing 1x vibration, or phase relationship across the coupling. Angular misalignment may look like a fretting fracture near the bolt hole.

Foundation setting, thermal movement, loose anchor bolts, poor initial alignment, and pipe strain are often the causes of this coupling ailment. You can prevent angular misalignment from affecting your couplings by reviewing the thermal growth values and checking both sides’ run-out and parallel offset.

Torsional Oscillation

Torsional oscillation may be difficult to detect without proper torque measurements, but you might notice fractures in the centre of the disc link and clamping area. An existing torsional issue, motor slip, and agitation from the VFD drive may cause torsional Oscillation.

It is hard to know whether your couplings are already suffering from this ailment, so it is best to take immediate corrective actions. Reviewing the torsional, tuning the coupling’s stiffness, checking the VFD drive parameters, and troubleshooting the torque monitor systems should help. 

Get Couplings at Poly Flex Now!

Couplings are critical and must always be kept in good condition to avoid issues. Are you looking for high-quality couplings designed for marine and industrial driveline applications in Australia? Take a look at Ploy Flex’s offers on their website.