Integrated Drive Generator
While in flight, engine driven generators provide the normal source of AC electrical power. Each engine has one integrated drive generator attached to the accessory case.
Each IDG is comprised of two sections:
- Constant Speed Drive
- Generator
The IDG internal oil system is used not only in the CSD, but also for cooling and lubricating the IDG itself. The oil is routed to an air/oil heat exchanger located in the fan section of the engine before entering the IDG Oil Cooler where it uses fuel to decrease temperature.
Should the temperature of the oil exceed a predetermined limit, the IDG will disconnect automatically. Alternatively, the IDG can be disconnected manually.
Note that the engine must be operating to disconnect an IDG. Additionally, electrical power must be applied to the aircraft and the respective engine start lever must be in IDLE.
Once disconnected, it is not possible to reconnect the IDG in flight; it must be accomplished on the ground by maintenance personnel.
The DRIVE light on the IDG panel indicates:
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- IDG low oil pressure, or
- Under frequency condition
The DRIVE light will illuminate from low oil pressure caused by any of:
- IDG Failure
- Engine shutdown
- IDG auto disconnect due high oil temp
- IDG disconnected via
DISCONNECTswitch.
