DOC AIRBUS | AMM A320FINTEGRATED DRIVE GENERATOR SYSTEM (IDG, GCU) - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
Each engine (HP rotor) drives its associated Integrated Drive Generator (IDG) through the accessory gearbox. The drive speed varies according to the engine rating.
The IDG provides a 115/200VAC, 3-phase, 400 Hz AC supply.
The IDG has two parts: the Constant-Speed Drive (CSD) and the generator.
The hydromechanical Constant-Speed Drive (CSD) drives the AC generator at constant speed.
** ON A/C NOT FOR ALL Each engine (HP rotor) drives its associated Integrated Drive Generator (IDG) through the accessory gearbox. The drive speed varies according to the engine rating.
The IDG provides a 115/200VAC, 3-phase, 400 Hz AC supply.
The IDG has two parts: the Constant-Speed Drive (CSD) and the generator.
The hydromechanical Constant-Speed Drive (CSD) drives the AC generator at constant speed.
2. Component Location
The IDG system is attached to the engine fan case:
** ON A/C NOT FOR ALL The IDG system is attached to the engine fan case:
IDG Location in Nacelle- the IDG is installed on the engine gearbox pad; it is attached by means of a Quick Attach Detach (QAD) adapter,
- the IDG cables are between the IDG and the electrical receptacle on the aircraft pylon,
- the fuel-cooled IDG oil cooler is a part of the engine heat management system,
- the fuel-cooled IDG oil cooler tubes connect the IDG to the fuel-cooled IDG oil cooler,
- the IDG oil temperature thermocouple is installed in the fuel-cooled IDG oil cooler.
| FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 5XT | P/BSW-ELEC/IDG 1 | 35VU | 210 | 24-21-00 | |
| 6XT | P/BSW-ELEC/IDG 2 | 35VU | 210 | 24-21-00 | |
| 4000XU | IDG | 435 | 24-21-51 | ||
| 4015KS | THERMOCOUPLE-IDG OIL TEMPERATURE | 410 | 24-21-15 | ||
| 6003EM | FCOC | 437AL | 435 | 79-21-43 | |
3. System Description
A. Integrated Drive Generator (IDG)
(1) The IDG converts the variable-speed shaft power directly into constant frequency 400 Hz AC electrical power.
The Constant Speed Drive (CSD), in the IDG, drives the AC generator at constant speed.
Thus, the AC generator produces constant frequency power.
The Constant Speed Drive (CSD), in the IDG, drives the AC generator at constant speed.
Thus, the AC generator produces constant frequency power.
B. Fuel-Cooled IDG Oil Cooler
(1) The fuel-cooled IDG oil cooler cools the IDG oil and limits the IDG inlet temperature. As the oil goes through the oil cooler, heat is transferred from the oil to the fuel. Then the cooled oil returns to the IDG.
NOTE: The normal IDG oil-inlet temperature is between 70 deg.C and 105 deg.C.
C. Generator Control Unit (GCU)
Each GCU controls its dedicated IDG:
Each GCU controls its dedicated IDG:
- IDG 1: GCU 1
- IDG 2: GCU 2
The GCU has these main functions: - regulation of the generator voltage at Point Of Regulation (POR)
- monitoring and protection of the system.
D. IDG Pushbutton Switches
If an IDG is faulty (overheat or abnormal oil low pressure), the FAULT legend of the IDG pushbutton switch comes on. The pilot must then open the safety guard and push the IDG pushbutton switch. This action results in the mechanical disconnection of the faulty IDG.
If an IDG is faulty (overheat or abnormal oil low pressure), the FAULT legend of the IDG pushbutton switch comes on. The pilot must then open the safety guard and push the IDG pushbutton switch. This action results in the mechanical disconnection of the faulty IDG.
NOTE: With engine stopped, the IDG cannot be disconnected. An underspeed condition inhibits the disconnection.
4. Power Supply
** ON A/C NOT FOR ALL
5. Interface
A. Generator Control Unit
(1) Input data
Each GCU receives the following signals from its dedicated IDG:
Each GCU receives the following signals from its dedicated IDG:
- oil inlet temperature,
- oil outlet temperature,
- low oil pressure,
- PMG 3 phase output voltage,
- CT 3 phase signal.
(2) Output data
Each GCU provides the following output analog data to the SDACs, through the ARINC 429 link:
It provides also to the SDACs the following discrete information through ARINC 429 link:
Each GCU provides the following output analog data to the SDACs, through the ARINC 429 link:
- IDG oil output temperature,
- IDG oil inlet temperature,
- AC load at POR,
- AC frequency (phase A)
- AC voltage (phase A) at POR.
It provides also to the SDACs the following discrete information through ARINC 429 link:
- overload warning,
- generator fault,
- IDG disconnect status,
- IDG disconnect pushbutton position,
- IDG oil outlet overheat,
- IDG oil low pressure,
- GEN pushbutton switch position.
6. Description
(1) Electrical circuit
- hook-up of the electrical wiring,
- location of the electrical connectors.
(2) Maintenance
- oil replenishing
- oil drainage
- oil level check
- filter
- disconnect reset handle.
(3) Inspection
- Differential Pressure Indicator (DPI) of the oil filter on the IDG oil-out line.
(4) Cooling system
- oil inlet port,
- oil outlet port.
B. Quick Attach Detach (QAD) Adapter
The IDG is installed on the engine gearbox pad. It is attached to the gearbox by means of a QAD adapter with a tension bolt.
The IDG is installed on the engine gearbox pad. It is attached to the gearbox by means of a QAD adapter with a tension bolt.
C. Drive
A mechanical epicyclic differential-gear transmits power to the generator of the IDG.
The speed of mechanically-coupled twin hydraulic-sub-assemblies modify the differential-gear output speed. Each sub-assembly consists of a hydraulic swashplate pump/motor: one with a fixed and the other with a variable swash angle.
The input shaft has a shear neck. Its primary duty is to protect the engine gearbox. But it is also used to protect the IDG against damage.
This figure shows the speed regulation loop.
A mechanical epicyclic differential-gear transmits power to the generator of the IDG.
The speed of mechanically-coupled twin hydraulic-sub-assemblies modify the differential-gear output speed. Each sub-assembly consists of a hydraulic swashplate pump/motor: one with a fixed and the other with a variable swash angle.
The input shaft has a shear neck. Its primary duty is to protect the engine gearbox. But it is also used to protect the IDG against damage.
This figure shows the speed regulation loop.
D. Generator
The generator is a three-stage assembly which has three machines connected in cascade.
The first machine (Pilot Exciter (PE)) is a twelve-pole Permanent Magnet Generator (PMG).
Its rotor is constructed of small Rare Earth Cobalt magnets. The output from the PE stator winding:
Thus, the main alternator receives excitation for the rotating salient four-pole field from the rectified output of the main exciter.
The main alternator has a three-phase star-connected stator winding. The three phases and star point neutral are taken to the generator output terminal block.
The generator is designed for use with an external voltage regulator which is part of the GCU.
The GCU:
The generator is a three-stage assembly which has three machines connected in cascade.
The first machine (Pilot Exciter (PE)) is a twelve-pole Permanent Magnet Generator (PMG).
Its rotor is constructed of small Rare Earth Cobalt magnets. The output from the PE stator winding:
- has a generator excitation function,
- provides power for other components of the electrical system (supply of the GCU and the external relays and contactors).The generator is thus "self-flashing" and "self-sufficient".
Thus, the main alternator receives excitation for the rotating salient four-pole field from the rectified output of the main exciter.
The main alternator has a three-phase star-connected stator winding. The three phases and star point neutral are taken to the generator output terminal block.
The generator is designed for use with an external voltage regulator which is part of the GCU.
The GCU:
- rectifies the output of the pilot exciter,
- regulates the excitation current to the main exciter field winding.
E. Servo Valve
(1) Generator speed control
The generator speed is controlled by a system composed of a servo valve in the IDG and an electronic control circuit in the GCU which positions the wobbler of the variable displacement hydraulic unit.
The generator speed is controlled by a system composed of a servo valve in the IDG and an electronic control circuit in the GCU which positions the wobbler of the variable displacement hydraulic unit.
(2) Function of the electronic control circuit
The electronic control circuit monitors the generator PMG frequency and compares this frequency to a reference source. Based on the error signal obtained, the control circuit then biases the servo valve to increase or decrease the control piston pressure as necessary to return the generator frequency to 400 Hz.
The electronic control circuit monitors the generator PMG frequency and compares this frequency to a reference source. Based on the error signal obtained, the control circuit then biases the servo valve to increase or decrease the control piston pressure as necessary to return the generator frequency to 400 Hz.
F. Electrical Connectors
There are three differently-sized electrical connectors on the IDG.
There are three differently-sized electrical connectors on the IDG.
(1) Connector A
The following internal components are connected to it:
The following internal components are connected to it:
- the Main Exciter (ME),
- three current transformers,
- the servo valve,
- the disconnect solenoid.
(2) Connector B
The following internal component are connected to it:
The following internal component are connected to it:
- the PMG stator
- the oil-in and oil-out temperature bulbs
(3) Connector C
Only one internal component is connected to it:
Only one internal component is connected to it:
- the charge pressure switch.
G. IDG Oil System
A fuel-cooled IDG oil cooler located near the IDG is used to cool the IDG oil.
The schematic of the IDG oil system is shown on figure
A fuel-cooled IDG oil cooler located near the IDG is used to cool the IDG oil.
The schematic of the IDG oil system is shown on figure
(1) IDG oil system operation
The IDG has a self-contained oil system except for the fuel-cooled IDG oil cooler.
Positive displacement scavenge-pumps deliver the oil (via the IDG oil filter) to the fuel-cooled IDG oil cooler and return it to the IDG.
The lubrication jets are individually supplied.
The dearator provides the inlet of the charge pump with cleaned, cooled and deaerated oil.
The charge pump pressurizes the oil against the charge relief valve.
It thus provides regulated supply pressures to:
When pressure rises, the valve opens so the cooler is bypassed during cold oil operation.
A scavenge pump relief-valve limits the supply pressure of the scavenge system.
A vent valve releases internal case pressure if necessary.
The IDG has a self-contained oil system except for the fuel-cooled IDG oil cooler.
Positive displacement scavenge-pumps deliver the oil (via the IDG oil filter) to the fuel-cooled IDG oil cooler and return it to the IDG.
The lubrication jets are individually supplied.
The dearator provides the inlet of the charge pump with cleaned, cooled and deaerated oil.
The charge pump pressurizes the oil against the charge relief valve.
It thus provides regulated supply pressures to:
- the differential hydraulic units,
- the control piston,
- the generator,
- the governor,
- the various lubrication and cooling nozzles.
When pressure rises, the valve opens so the cooler is bypassed during cold oil operation.
A scavenge pump relief-valve limits the supply pressure of the scavenge system.
A vent valve releases internal case pressure if necessary.
(2) IDG oil-pressure fill
A quick fill coupling installed on the transmission casing enables pressure filling or topping up the unit with oil. The oil thus introduced flows to the transmission via the filter and external cooler circuit. This ensures:
A quick fill coupling installed on the transmission casing enables pressure filling or topping up the unit with oil. The oil thus introduced flows to the transmission via the filter and external cooler circuit. This ensures:
- the priming of the external circuit,
- the filtration of any oil introduced.
NOTE: Motoring is not necessary for oil level check or oil replenishment.
(3) Oil filter differential pressure indicator
The scavenge filter is fitted with an oil filter differential pressure indicator. The indicator shows when the filter element requires replacement. The sensing device for the oil filter differential pressure indicator is automatically inhibited during cold oil running conditions. This avoids spurious operation due to high oil viscosity.
The scavenge filter is fitted with an oil filter differential pressure indicator. The indicator shows when the filter element requires replacement. The sensing device for the oil filter differential pressure indicator is automatically inhibited during cold oil running conditions. This avoids spurious operation due to high oil viscosity.
(4) Oil level check
The oil level can be read on the vertical sight glass.
Servicing is performed according to the oil level position in zones determined by different colors (red, yellow, green).
The oil level can be read on the vertical sight glass.
Servicing is performed according to the oil level position in zones determined by different colors (red, yellow, green).
(5) Disconnect reset handle
A mechanical reset handle is fitted to the IDG.
The handle enables the drive to be reconnected while the engine is shut down and stationary on the ground.
A mechanical reset handle is fitted to the IDG.
The handle enables the drive to be reconnected while the engine is shut down and stationary on the ground.
H. IDG Feeder Cables
(1) The terminals on each end of the IDG feeder cables are different. On one end, they connect to the IDG, while on the other end they connect to the aircraft pylon electrical-connector.
I. Fuel-Cooled IDG Oil Cooler Tubes
(1) All six IDG oil-cooler tubes are rigid metal tubes. The tubes which attach to the fuel-cooled IDG oil cooler have a three-bolt flange connection at one end. The three-bolt flange connections have an alignment boss and a groove for the installation of a seal ring. All the other ends of the tubes have the usual (male or female) flareless tube connections. Three of the tubes are 0.625in. in diameter and three are 0.75in. in diameter. Four of the tubes also have support brackets attached to them: two tubes have one bracket each and two tubes have three brackets each.
J. IDG Oil Temperature Thermocouple
(1) The thermocouple has a two-bolt installation flange, an electrical receptacle and a thermocouple protection cover. The unit is a sealed assembly and it cannot be disassembled. The electrical receptacle connects with an electrical connector from the engine electrical harness. The thermocouple assembly attaches to the fuel-cooled IDG oil cooler with the two-bolt flange. The cover seals the unit from the oil and protects it from contamination and other damage.
7. Operation/Control and Indicating
A. Fuel-Cooled IDG Oil Cooler
The fuel-cooled IDG oil cooler is monitored by the IDG oil-temperature thermocouple to keep the IDG oil temperature in the tolerance.
The fuel-cooled IDG oil cooler is monitored by the IDG oil-temperature thermocouple to keep the IDG oil temperature in the tolerance.
B. IDG Oil Temperature Thermocouple
(1) The thermocouple is a device which changes a temperature input into an electrical output. It gives an electrical output to the EEC, in relation to the temperature of the oil in the fuel-cooled IDG oil cooler. When the temperature of the oil changes, the electrical output of the thermocouple changes. The electrical output of the thermocouple changes in relation to the oil temperature input.
NOTE: For the EEC, see 73-20-00
C. Monitoring of the Oil System Operation
An oil temperature sensor monitors the oil inlet temperature and an other one, the oil outlet temperature.
The second provides ADVISORY oil temperature and oil overheat detection.
A pressure switch operates in the event of a low charge oil pressure.
In case of:
An oil temperature sensor monitors the oil inlet temperature and an other one, the oil outlet temperature.
The second provides ADVISORY oil temperature and oil overheat detection.
A pressure switch operates in the event of a low charge oil pressure.
In case of:
- abnormally low oil-pressure or,
- IDG oil overheat (outlet temperature > or = 185 °C),
the warnings are provided to the cockpit (FAULT legend on the corresponding IDG pushbutton switch, MASTER CAUT light, single chime and messages on the ECAM upper display unit and ECAM lower display unit.
The oil outlet temperature is displayed on the ELEC page on the lower ECAM display unit.
NOTE: When the oil temperature reaches a predetermined value (147 °C) , an advisory mode is available on the lower ECAM display unit.
D. Disconnection
To disconnect the defective IDG, the operator must:
The "DISC" indication comes into view on the "ELEC" page on the lower ECAM DU.
The IDG disconnection is irreversible in flight. The operator cannot disconnect the IDG below the underspeed threshold.
If the IDG operates for more than 50 hours in the disconnected mode without a reset, the operator must replace it and send the removed IDG for a shop inspection. This is because there is a risk of damage to the ball bearing assembly on the input shaft and to the aircraft engine. After the IDG disconnection, the operator must not connect it again.
To disconnect the defective IDG, the operator must:
- Open the safety guard.
- Push the IDG 1(2) pushbutton switch on the ELEC section of overhead panel 35VU.
The "DISC" indication comes into view on the "ELEC" page on the lower ECAM DU.
The IDG disconnection is irreversible in flight. The operator cannot disconnect the IDG below the underspeed threshold.
If the IDG operates for more than 50 hours in the disconnected mode without a reset, the operator must replace it and send the removed IDG for a shop inspection. This is because there is a risk of damage to the ball bearing assembly on the input shaft and to the aircraft engine. After the IDG disconnection, the operator must not connect it again.
E. Reconnection of the IDG
A mechanical reset handle is fitted to the IDG. The handle is used to reconnect the drive while the engine is stationary on the ground.
A mechanical reset handle is fitted to the IDG. The handle is used to reconnect the drive while the engine is stationary on the ground.
NOTE: The system can only be reconnected on the ground with the related engine shut down.
F. Oil Filter
A clogged filter indication is provided by a local visual differential pressure indicator (DPI). The indicator is installed opposite the drive end of the IDG.
A clogged filter indication is provided by a local visual differential pressure indicator (DPI). The indicator is installed opposite the drive end of the IDG.