The LORD balancing system instantaneously corrects imbalances in rotating equipment while in operation, which is faster and more effective than conventional “off-line” balancing techniques. By operating on-line and automatically, the balancing system provides optimal operation by compensating for variations in balance throughout the entire operating range of rotating equipment. The system includes a small electronic controller that not only achieves online balancing, but also can serve as a predictive maintenance tool. As the system nears maximum balancing capacity, the controller triggers a call for maintenance before the rotating equipment actually needs to be repaired. Benefits of the system are less fatigue for both on-engine and on-board equipment, lower failure rates and reduced operating costs.
Ground Test
An initial ground test of LORD Corporation’s new Balancing Technology validated its ability to minimize vibration during typical flight cycles. The ground test was conducted in September 2001 on a 5000shp Hamilton Sundstrand propeller that is to eventually replace the 54H60 series for the E-2, C-2, C-130 and P-3 series of aircraft. NAVAIR supported LORD in conducting what was the first field demonstration of the the balancing technology for aircraft propellers. The once per revolution (P) vibration levels were reduced by almost an order of magnitude over the full power range from reverse thrust to full takeoff power.
Propellers are somewhat unique in that significant amounts of unbalance result from their variable blade pitch, which can cause changes in both mass imbalance and aerodynamic imbalance. A wide variation in the required balance correction amplitude and angular position was indeed observed during the test. The balancer was able to actively respond to these variations and implement such variation in the balance correction, keeping the propeller vibration at minimal levels. Active balancing is thus the only way to properly balance propellers throughout their operating range.
The traditional method of propeller balancing optimizes balance for one condition, often optimized only on the ground. In contrast, LORD Corporation’s balancing system operates on-line, automatically adjusting to all the variation and conditions of a typical flight cycle. Since it is automatic, the process occurs continuously throughout the full operating range of the rotating equipment without human intervention or downtime. Furthermore, the controller module constantly monitors vibration and triggers a balance correction only when the vibration reaches a predetermined level. Any power shutdown or controller shutdown leaves the balance correction at its latest optimal value, thus providing for graceful performance degradation and completely fail-safe operation.