DOC AIRBUS | AMM A320FPNEUMATIC STARTER AND VALVE SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The starter and valve system is part of engine starting system (Ref. AMM D/O 80-00-00-00).
** ON A/C NOT FOR ALL The starter and valve system is part of engine starting system (Ref. AMM D/O 80-00-00-00).
2. System Description
During starts, an electrical signal is sent to the Starter Air Valve (SAV) to open the valve. Air is supplied down the Starter Air Duct (SAD), flows through the SAV and turns a micro-turbine rotor in the Air Turbine Starter (ATS).
The ATS has a torsion shaft with a spline gear that is connected to the Accessory Gearbox (AGB). The rotation of the ATS rotor turns the AGB gears while the radial drive shaft receives torque, which causes core engine rotation.
When the engine rotation has reached a sufficient speed, the fuel and ignition systems are engaged in a given schedule to get light-off.
** ON A/C NOT FOR ALL During starts, an electrical signal is sent to the Starter Air Valve (SAV) to open the valve. Air is supplied down the Starter Air Duct (SAD), flows through the SAV and turns a micro-turbine rotor in the Air Turbine Starter (ATS).
The ATS has a torsion shaft with a spline gear that is connected to the Accessory Gearbox (AGB). The rotation of the ATS rotor turns the AGB gears while the radial drive shaft receives torque, which causes core engine rotation.
When the engine rotation has reached a sufficient speed, the fuel and ignition systems are engaged in a given schedule to get light-off.
3. Component Description
A. Air Turbine Supply
The starter air supply, which is controlled by the SAV upstream of the starter, operates an axial turbine in the starter.
The main function of the ATS is to provide torque to the AGB for engine core rotation. The torque that the turbine provides is transmitted through a planetary reduction-gear set and an overrunning clutch to a splined output shaft, which engages with the AGB.
An internal recirculating shared oil supply system lubricates the starter bearings, gears, clutch, and splines, with make-up oil from the AGB. The oil fill port is only used one time, during the initial installation onto the AGB, and no lubrication servicing task will be necessary due to the shared oil supply system.
The overrunning clutch disconnects the turbine and planetary gear set from the output shaft when the engine starting sequence is completed.
The function of the chip detector plug is to get magnetic particles for inspection to show internal damages within the ATS.
The starter air supply, which is controlled by the SAV upstream of the starter, operates an axial turbine in the starter.
The main function of the ATS is to provide torque to the AGB for engine core rotation. The torque that the turbine provides is transmitted through a planetary reduction-gear set and an overrunning clutch to a splined output shaft, which engages with the AGB.
An internal recirculating shared oil supply system lubricates the starter bearings, gears, clutch, and splines, with make-up oil from the AGB. The oil fill port is only used one time, during the initial installation onto the AGB, and no lubrication servicing task will be necessary due to the shared oil supply system.
The overrunning clutch disconnects the turbine and planetary gear set from the output shaft when the engine starting sequence is completed.
The function of the chip detector plug is to get magnetic particles for inspection to show internal damages within the ATS.
B. Starter Air Valve
The main function of the SAV is to control the airflow directed to the air turbine starter. In addition, the SAV has the capability to open to an intermediate position based on input from the EEC-channel in control. The intermediate position is required for sub-idle-speed bowed rotor-motoring, in advance of the start sequence progressing to light-off. Bowed rotor results from thermo-elastic deformation of core structures during engine soak back.
The SAV is a solenoid controlled, air actuated, butterfly valve. Redundancy is provided by a dual channel solenoid for improved dispatch reliability.
A dual-channel pressure transducer provides closed position indication to both EECs (channel A and channel B). The SAV failsafe position is closed in the event of loss of solenoid control or transducer feedback signal.
An external wrench connection (manual override) is provided for manual opening or closing of the SAV.
The main function of the SAV is to control the airflow directed to the air turbine starter. In addition, the SAV has the capability to open to an intermediate position based on input from the EEC-channel in control. The intermediate position is required for sub-idle-speed bowed rotor-motoring, in advance of the start sequence progressing to light-off. Bowed rotor results from thermo-elastic deformation of core structures during engine soak back.
The SAV is a solenoid controlled, air actuated, butterfly valve. Redundancy is provided by a dual channel solenoid for improved dispatch reliability.
A dual-channel pressure transducer provides closed position indication to both EECs (channel A and channel B). The SAV failsafe position is closed in the event of loss of solenoid control or transducer feedback signal.
An external wrench connection (manual override) is provided for manual opening or closing of the SAV.