Piper Malibu Meridian PA-46-500TP Airplane Maintenance Manual page 1461

PIPER AIRCRAFT, INC.
PA-46-500TP, MALIBU MERIDIAN
MAINTENANCE MANUAL
GENERAL
Description and Operation
The ignition system consists of one exciter box, two ignition leads and two spark igniters. Both igniters
are engaged simultaneously. DC power is delivered to the exciter box from the essential bus through an
ignition mode selector switch in the engine control switch panel and a torque pressure switch. While in
the Automatic ignition mode, the ignition system will activate when the torque is less than or equal to
approximately 275 ft. lbs., and deactivate when the torque is greater than or equal to approximately 375
ft. lbs. Continuous ignition, at any torque setting, is provided in the Manual ignition mode.
The exciter is a sealed unit consisting of electronic components encased by an epoxy resin. When
energized, a capacitor in the unit is progressively charged until it reaches a predetermined value, when
the energy stored is sufficient to ionize a spark gap in the unit and discharge the capacitor across two
spark igniters. The design of the system permits continued operation of one spark igniter if the other
stops functioning.
The high tension cable assemblies carry an electrical charge from ignition exciter to spark igniters. The
cable consist of an electrical lead contained in a flexible metal braiding, with coupling nuts on each end
and mounting flanges for attachment to engine fire seals.
The spark igniters are located at the 4 and 9 o'clock positions on the gas generator case adjacent to fuel
manifold.
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7G7 Apr 15/07