Torque limiters are critical elements in rotational machine assemblies that protect against instantaneous overload conditions.
Overloads are often multivariable and caused by both mechanical and electrical factors. Therefore, a torque-limiting switch is implemented to mitigate potential overload damage, regardless of the root cause. Limiters establish a peak value for torque-generated force in a system.
Rotational components operate uninterrupted within the bounds of the set torque limit. When the limit is exceeded, the operating machine is immediately detached from the load. The load separation stops the overload cascade from surging through the system, avoiding potential damage to the machine and its operators.
Proper maintenance and repair scheduling of limiter components should be prioritized in any heavy-duty, high-cycle operation. Machine troubleshooting can be conducted after a power failure, but any resulting damage cannot be undone. Effective use of a torque limiter circumvents much of the risk inherent to equipment failures.
Torque limiters are mostly autonomous but are not immune to malfunction or regular wear and tear. Several operative signals may indicate your torque limiter needs repair or replacement.
1. Abnormal Sounds at Start-Up
A sudden separation from loading elements is not a gentle process. During successful operation, torque limiters generate noise – and this should be expected.
On occasion, a torque-based system may emit a grinding, slamming, screeching, or whirring noise on start-up. These sounds can be accompanied by non-typical rumbling or physical motion in the equipment (as if a component was being tossed around). However, if the system is operating beneath the torque threshold set by the limiter, there should be no rattling, slipping, or squealing from the protective component.
Assess the characteristics of the noise and when it occurs. For example, if there are consistent noises at start-up, the torque limiter may be improperly installed, damaged, or over-slipping.
2. Motor Will Not Turn-Over / Start
Depending on the equipment, the torque limiter may be implicated in no-start conditions.
For example, electric engines that demand maximal torque at start-up – zero revolutions – may trigger immediate slippage by the torque limiter. As a result, the motor will be unable to turn over. A no-start might be accompanied by the sounds noted above, ignition chugging, or another rattling in the equipment.
3. Torque Limiter Slippage
Torque limiters are designed to slip – that’s how they can disengage from the load component. However, a total slippage of the limiter can mean operators will be unable to start or re-engage the equipment. Thus, slippage is undesirable below the set torque threshold. Coincidentally, over-slippage tends to be responsible for many situations involving abnormal noises and no-start motor conditions.
The type of torque limiter affects the mode of slippage. For example, friction plate, magnetic particle, and magnetic hysteresis torque limiters use different slip mechanisms to achieve the same operational goal.
Kor-Pak Torque Limiter Services
Troubleshooting points of failure in heavy equipment is a punishing process regarding downtime and operational costs.
Kor-Pak is equipped with the resources to provide consultative, repair, and replacement services for your torque limiters. Contact us for more information.