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.