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Old 2nd Dec 2008, 13:55
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celtic mech
 
Join Date: Jan 2006
Location: Ireland
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Just for info for anyone wanting basic info on the starter. taken from the AMM customized for GE engines..

Operation

(1)
Starter

(Ref. Fig. 003 SHEET 003.1)
The inlet housing assembly directs the flow of compressed air to the stator assembly which, in turn, directs the air flow into the blades of a turbine wheel. The air flow produces a high speed and low torque rotation of turbine wheel. Exhaust air is released to ambient at approximately ambient pressure. The pinion gear, the three matched planetary gear set, three low speed pinions and internal gear hub transform the high speed rotation (with low torque) of turbine wheel into low speed and high torque at output shaft. The drive shaft assembly provides disengagement of output shaft assembly from internal gear hub. The disengagement occurs after the air to the starter is shut off and when the engine speed exceeds pawl lift-off speed of drive shaft assembly. This type of disengagement allows the output shaft assembly to rotate with the engine HP rotor while the gear, the internal gear hub, the planetary gear and turbine wheel coast to stop. The inlet housing incorporates an axial containment ring with tungsten carbide cutter pins to provide turbine wheel containment at speeds up to the maximum turbine free running speed. Should the turbine wheel moves axially after a thrust bearing failure, the cutter pins will cut the rim from the turbine wheel and the separated parts shall be contained within the enclosed space of the axial and radial containment ring. The sealing of the starter is ensured at output shaft assembly by a carbon seal. A magnetic plug in the gear housing provides protection for the bearings by collecting any metallic particles contained in the lubricant. Thus a simple inspection of the magnetic plug for the metal particles provides a quick easy method to detect starter failures while the sight glass provides oil level indication.

(a)
Lubrication

The lubrication is a wet sump splash type system. The lubricating oils shown in Table below are those which are approved for use in air turbine starters. They are listed by brand names. Type 2 lubrication oils per MIL-L-23699 are preferred. Type 2 oils provide higher viscosity and result in better lubrication at high temperatures.

(b)
Physical and operational characteristics

Turbine type: single stage axial flow
Reduction gearing: compound planetary
Internal engagement: pawl and ratchet type
Drive shaft disengagement speed: 35.1% to 44.7% N2
Drive shaft reengagement speed: 30% N2 or less
Direction of output shaft rotation: CCW when viewing the starter output shaft.


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