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MAINTENANCE MANUAL
G81565
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MAINTENANCE MANUAL
N .A
T1 CURRENT
3., 1200 HZ .B
TRANSFORMER TO GENERATOR
8 VAC T2 CIRCUIT BREAKER
ASSEMBLY .C
(NO LOAD)
T3
120/208V AC
3. 400HZEXCITER
MAINFIELD
DC ROTATING NEUTRALRECTIFIERS
ROTATINGROTOR
RECTIFIERSSHAFT
PERMANENTMAGNETICGEN (PMG)
IDG PERMANENTMAGNETGENERATOR SHORTED POINT OFFREQ
PMG REGULATIONMAIN
LOAD MONITORING
SENSE
PHASE VOLTAGE GENERATOR
AND PROTECTION
DETECT SENSING
EXCITER
POWER GENERATOR SUPPLY TRIP
SHORTEDROTATING 28V DC
CB1
DIODE BAT BUS
DETECT
GCB, BTBCB2
AND CONTROL
MAIN SWITCH PWR
EXCITERFIELD VOLTAGEPOWER REGULATORSUPPLY GENERATOR FIELD SWITCH
HARDWARENI
SOFTWARE
T
E
CLOSE
R
GENERATOR FIELD OFF LIGHT F
GCR
GCR
CONTROL CA
LOGIC
E
GEN CONT SWITCH
GENERATOR CONTROL UNIT
IDG Power Generation Block Diagram
Figure 3
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MAINTENANCE MANUAL
Pressurized oil is used for integrated drive generator (IDG) lubrication, cooling, and control. The IDG charge system supplies this oil to the speed control and power generation sections. If this charge pressure falls below 140 |20 psi, a ground circuit in the IDG closes. A signal is sent to the generator control unit, causing the approriate amber DRIVE light in the GEN DRIVE DISC switch to come on. The switch is on electrical systems panel M10063. (The M10063 panel is on pilots' overhead panel P5). In addition to the DRIVE light, the EICAS display will show a level C alert: L (or R) GEN DRIVE (Ref 31-41-00). (The appropriate engine must be running for the EICAS message to appear. This message results in an ELEC AUTO EVENT in the EICAS system). To avoid further damage to the IDG, the guarded GEN DRIVE DISC switch should be pressed. This activates the input disconnect mechanism.
(7)
The input disconnect mechanism disconnects the IDG input shaft from the drive section of the IDG. This removes mechanical input power from the IDG. The mechanism is controlled by two guarded GEN DRIVE DISC switches on M10063. These switches are momentary action type, pushing a switch once activates the disconnect. The GEN DRIVE DISC switch should be pushed when the amber DRIVE light in the switch is on. The light is on when charge pressure falls below 140 psi, or IDG oil-out temperature reaches 365 | 9°F (185°|5°C). An EICAS level C alert also appears (if the corresponding engine is running): L (or R) GEN DRIVE. Failure to disconnect the IDG can further damage it. (The EICAS message results in an ELEC AUTO EVENT in the EICAS system).
(8)
GUN 001-007 POST-SB 24-59; GUN 008-999; An inhibit IDG disconnect circuit is provided, using the engine running relay to avoid nuisance disconnects when the engine is not running.
(9)
After the input disconnect mechanism has been activated, the IDG input shaft and the CSD section of the IDG can only be reconnected on the ground. This is done by pulling the input drive disconnect reset ring fully out. This ring is on the IDG housing.
(10)
A disconnected IDG that remains mounted to an engine for about 50 flight hours can receive damage to the ball bearing assembly for the IDG input shaft.
(11)
Oil exiting the IDG flows through the IDG scavenge filter. The oil then goes through the air/oil heat exchanger. A delta-pressure indicator, is used to indicate a clogged scavenge filter. The delta-pressure indicator is located next to the filter housing. The indicator causes a red button to pop out, if the pressure across the filter reaches 60 psig. This shows that the filter is clogged. The indicator is prevented from operating when oil temperature is below 145°F (63°C).
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