Turbine Engine Automated Trim Balancing and Vibration Diagnostics

After turbine engine is overhauled at Oklahoma City Air Logistics Center (OC-ALC) or at San Antonio Air Logistics Center (SA-ALC), it is run in the test cell before shipment. While in the test cell, final adjustments are made to the engine. One of these adjustments is the dynamic vibration balance of the engine. This adjustment is referred to as a trim balance. The current trim balance procedures in use at OC-ALC require the engine to be in the test cell from 4 to 6 hr. This paper presents a new automated procedure which has demonstrated a reduction in test cell time by 60 to 80 percent. In addition, engines which cannot be trim balanced must be returned to the overhaul line for partial disassembly and rework. The diagnostic guidance provided to the rework line is highly subjective and dependent on operator experience. Uncertain problem definition often results in rejecting the same engine several times. The new procedure described in this paper shows promise for automating vibration diagnostics. This would allow definitive guidance to be provided to the rework line and reduce repeated rejects of the same engine. The Automated Trim Balancing and Diagnostic Systems as designed for OC-ALC and SA-ALC have a projected multi-million dollar savings for the Air Force.