AC MAIN GENERATION - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General
The two engine generators provide the AC main generation. The AC main generation supplies the whole aircraft in normal flight configuration.
The transfer circuit supplies either one or the two distribution networks from any generation source:

main,
auxiliary,
or ground.

** ON A/C NOT FOR ALL

2. Component Location

AC Main Generation - Component Location ** ON A/C NOT FOR ALL

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
** ON A/C ALL
1XU1	GCU-1	91VU	121	24-22-34
1XU2	GCU-2	91VU	121	24-22-34
3XU1	P/BSW-ELEC/GEN 1	35VU	210	24-21-00
3XU2	P/BSW-ELEC/GEN 2	35VU	210	24-21-00
9XU1	GLC-1	120VU	212	24-22-55
9XU2	GLC-2	120VU	212	24-22-55
10XU	P/BSW-ELEC/BUS TIE	35VU	210	24-21-00
11XU1	BTC-1	120VU	212	24-22-55
11XU2	BTC-2	120VU	212	24-22-55
13XU	P/BSW-EMER ELEC PWR/GEN1 LINE	21VU	211	24-21-00
** ON A/C NOT FOR ALL
24XG	GAPCU	92VU	122	24-41-34
** ON A/C ALL
41XU1	CT-AC, 1		131	24-22-17
41XU2	CT-AC, 2		132	24-22-17
** ON A/C NOT FOR ALL
51XU1	CT		212	24-22-17
51XU2	CT		212	24-22-17
** ON A/C ALL
4000XU	IDG		435	24-21-51
** ON A/C NOT FOR ALL
22XU1	EGIU-1	95VU	121	24-22-33
22XU2	EGIU-2	96VU	122	24-22-33
** ON A/C NOT FOR ALL
42XU1	CT-AC, 1	120VU	212	24-22-17
42XU2	CT-AC, 2	120VU	212	24-22-17
42XU3	CT-AC, 1	120VU	212	24-22-17
42XU4	CT-AC, 2	120VU	212	24-22-17
50XU1	SENSOR-TDC AC, 1	103VU	126	24-22-18
50XU2	SENSOR-TDC AC, 2	103VU	126	24-22-18

** ON A/C NOT FOR ALL

3. System Description

AC Main Generation (Normal Configuration) - General Schematic ** ON A/C NOT FOR ALL

When the two engines run in normal conditions, generator 1 and generator 2 supply their own network.
Generator 1 supplies network 1, including:

AC BUS 1,
AC ESSENTIAL BUS,
AC SHEDDABLE ESSENTIAL BUS.

Generator 2 supplies network 2, corresponding to AC BUS 2.

Networks 1 and 2 are supplied in priority order:

by their generator,
by the electrical ground power unit,
by the auxiliary generator,
or by the other generator.

GEN1 and GEN2 pushbutton switches, on the panel 35VU on the overhead panel, control the generators 1 and 2 respectively via the GCU.
The EGIU transmit the main parameters from the GCU and generators to the ECAM system.

** ON A/C NOT FOR ALL

4. Component Description

A. Generator Control Unit FIN: 1-XU-1 FIN: 1-XU-2
The 3 GCUs are identical and interchangeable. The GCU functions (GCU1, GCU2, APU GCU) are selected by Pin Programming.
The GCU has four different functions:

Voltage regulation,
Control and protection of the network and the generator,
Control of the various indications,
System test and self-monitoring.

Voltage regulation is performed in the analog form, whereas the other functions are digital.
The GCUs are supplied:

Directly from the PMG, for generator excitation and 28VDC internal and external supply,
From the aircraft normal network (28VDC) for the internal and external supply.

This dual supply constitutes a back up supply.
The 2 GCUs are identical and interchangeable. The GCU functions (GCU1 and GCU2) are selected by Pin Programming.
The GCU has four different functions:

Voltage regulation,
Frequency regulation,
Control and protection of the network and the generator,
Control of the various indications,
System test and self-monitoring.

All these functions are performed in the digital form.
The GCUs are supplied:

Directly from the PMG, for generator excitation and 28VDC internal and external supply,
From the aircraft normal network (28VDC) for the internal and external supply.

This dual supply constitutes a back up supply.

(1) Voltage regulation
The voltage regulation is performed by regulating the generator excitation current: the voltage is kept at the nominal Point Of Regulation (POR). The POR is located in the electrical power center at the end of the generator feeder, upstream of the line contactor.
Analog circuits achieve the regulation. The PMG provides directly the excitation supply via the Generator Control Relay (GCR). The excitation supply is rectified. Then a chopper amplifier (pulse width modulation), protected by a freewheeling diode, controls the excitation supply.
The regulation is achieved using a signal proportional to the average of the three line to neutral voltages at the input.
NOTE :

During an operation in unbalanced rating, the voltage level of the higher phase is limited. This limit has a priority on the regulation of the three phase mean voltage.
A stabilization circuit enables the dynamic response of the regulation to be improved.
A current limiter circuit limits the current supplied by the generator. As the excitation current is limited, the mechanical power that the drive part supplies is also limited.
If the protection circuits detect a fault, the generator excitation is cut off:
. Electronically by shorting to ground the Voltage Regulation Shut Down: (VR S/D Down),
. By cutting off its supply by the GCR.
With a generator selected by the GEN pushbutton switch, the excitation command signal (VR S/D Line) is used to command:
. The initial generator excitation at engine start (when the generator frequency is more than 325Hz),
. The generator de-energization at engine shutdown (excitation cut-off when the generator frequency is less than 325Hz).

(2) Voltage regulation
The voltage regulation is achieved by controlling the current through the exciter field. The voltage is kept at nominal value (115VAC) at the Point of Regulation (POR).
The POR is located in the electrical power center (120VU) at the end of the generator feeder, upstream of the line contactor.
The principle of operation of the voltage regulator is by constant frequency variable pulse width modulation of the voltage through the exciter field.

(3) Regulation of the generator speed
The regulation of the generator speed is accomplished by means of a servo valve located in the IDG. The GCU controls the servo valve position. The operating principle is given in Ref. 24-21-00.

(4) Control and protective functions
The GCU controls the connection and disconnection of the power provided by the generator to and from the aircraft electrical system. This control is provided by means of 3 relays:

The Generator control relay (GCR) which controls the generator excitation,
The Power Ready Relay (PRR) which controls the generator line contactor and the FAULT warning light in the cockpit,
The Servo Valve Relay (SRV) which controls the generator speed by means of the servo valve.

(5) Generator control and protection functions
These functions are mainly the generator excitation and line contactor control.
The excitation is controlled via the GCR.
The line contactor is controlled via the Power Ready Relay (PR) which is energized when:

The speed is more than 4730 rpm and,
The GCR is closed.

Signals received or generated by the GCU control these two relays.

The following control or fault signals cause generator shutdown or de-energization:

Zone of Protection ** ON A/C NOT FOR ALL

IDG disconnection,
GLC failure (BTC is only locked out),
Engine shutdown with the ENG FIRE pushbutton switches (IDG position),
PMG short circuit,
Over/under voltage,
Over/under frequency,
Open cable (IDG position),
APU ready (APU position),
Differential protection:
. Zone 1 : Monitoring of the generator 1 or 2 and feeders,
. Zone 2 : Monitoring between the line contactor and the primary circuit breakers related to the channel. Monitoring between the BTC of the applicable channel and the primary circuit breakers,
GEN pushbutton switch,
Short circuit of the rotating diodes,
Phase sequence (in this case, the GCU opens the PR relay only).

Except in some particular cases, the system may be reset by setting the GEN pushbutton switch to OFF.

The PR is also controlled by the IDG drive underspeed. This prevents the generator from being energized.

NOTE: Each time the generator is de-energized because of a fault signal, do a GCU reset. To do this, push (ON) then release (OFF) the related GEN pushbutton switch.

NOTE: After:

Activation of a differential pressure, or
Activation of a GLC fault.

The system can be reset only two times via the GEN pushbutton switch.

A table listing all these functions is shown below.
GCU DETECTION:

------------------------------------------------------------------------------

! FUNCTION !SENSING ! THRESHOLD !TIME DELAY !TRIPS! REMARKS !INHIBITION!

!-----------!--------!-----------!-----------!-----!---------------!----------!

!Overvoltage!Highest ! 130VAC, ! Inverse ! GLC ! Turns off ! !

!(OV) !phase at! + or - !(compatible! GCR ! voltage ! !

! !POR ! 1.5V ! with the ! ! regulator ! !

!(IDG and ! ! ! guaranteed! ! ! !

! APU GEN) ! ! ! transient ! ! ! !

! ! ! ! voltage ! ! ! !

! ! ! ! to the ! ! ! !

! ! ! ! network) ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Undervol- ! Lowest ! 100VAC, !4 s to 5 s ! GLC ! Turns off ! !

! tage (UV) ! phase ! + or - ! ! GCR ! voltage ! !

! ! at POR ! 4V ! ! ! regulator ! !

! ! voltage! ! ! ! ! !

! (IDG and ! ! ! ! ! !Locked out!

! APU GEN) ! ! ! ! ! !by US TRIP!

! ! ! ! ! ! !APU TRIP !

! ! ! ! ! ! !or UP TRIP!

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Overfre- ! PMG ! PMG fre- !3 s to 5 s ! GLC ! Turns off ! !

! quency(OF)! fre- ! quency ! ! GCR ! voltage ! !

! (IDG and ! quency ! correspon-! ! ! regulator ! !

! APU GEN) ! ! ding to ! ! ! ! !

! ! ! (433Hz ! ! ! ! !

! ! ! + or - ! ! ! ! !

! ! ! 3Hz) ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Underfre- ! PMG ! PMG fre- !3 s to 5 s ! GLC ! Turns off !Locked out!

! quency(UF)! fre- ! quency ! ! GCR ! voltage !by US TRIP!

! (IDG and ! quency ! correspon-! ! ! regulator ! or !

! APU GEN) ! ! ding to ! ! ! !APU TRIP !

! ! ! (363Hz ! ! ! ! !

! ! ! + or - ! ! ! ! !

! ! ! 3Hz) ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Underspeed! IDG !4730 RPM !100 ms max.! GLC ! Generator ! !

! (US) ! input ! + or - ! ! ! excitation ! !

! (IDG) ! speed ! 30 RPM ! ! ! is cut off ! !

! !magnetic! ! ! ! through an UF ! !

! ! pick-up! ! ! ! signal at ! !

! ! ! ! ! ! frequency ! !

! ! ! ! ! ! below 325Hz ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Overload ! Average! 277A ! 13 s ! ! Signal for ! !

! (OL) ! of the ! + or - ! + or - ! ! warning and ! !

! (IDG and ! three ! 13A ! 3 s ! ! automatic gal-! !

! APU GEN) ! genera-! ! ! ! ley shedding ! !

! ! tor ! ! ! ! of APU GEN on ! !

! ! current! ! ! ! ground ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Phase se- !2 phases! A.B.C.N. ! None ! GLC ! Prevents GLC ! !

! quence(PS)!at POR ! phase ! ! ! closure if ! !

! ! ! sequence ! ! ! phase sequence! !

! (IDG and ! ! ! ! ! is not ABCN ! !

! APU GEN) ! ! ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Disconnect! Discon-! Manual ! None ! GLC ! Turns off vol-! !

! (D) (IDG) ! nect ! action ! ! GCR ! tage regula- ! !

! ! signal ! ! ! ! tor, turns on ! !

! ! from ! ! ! ! warning light ! !

! ! cockpit! ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Fire (F) ! Fire ! Manual ! None ! GLC ! Turns off vol-! !

! (IDG) ! signal ! action ! ! GCR ! tage regulator! !

! ! cockpit! ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Differen- ! Diffe- ! 45A ! 37.5 ms ! GLC ! Open BTC, GLC.! !

! tial Pro- ! rential! + or - ! + or - ! GCR ! If DP is in ! !

! tection ! current! 5A ! 2.5 ms ! BTC ! zone 1, then ! !

! (DP) ! of each! ! ! ! remove inter- ! !

! ! phase ! ! ! ! lock from BTC ! !

! ! from ! ! ! ! in 120+10 ms. ! !

! (IDG and !the CT's! ! ! ! If DP zone 2, ! !

! APU GEN) ! sensing! ! ! ! lockout GLC ! !

! ! ! ! ! ! and BTC ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Shorted ! Three ! Ripple ! 2 s ! GLC ! Turns off vol-! !

! Permanent ! phases ! of PMG -! + or - ! GCR ! tage regulator! !

! Magnet ! voltage! rectified ! 0.5 s ! ! ! !

! Generator ! PMG ! output ! ! ! ! !

! (S PMG) ! ! ! ! ! ! !

! (IDG and ! ! ! ! ! ! !

! APU GEN) ! ! ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Open Cable! Diffe- ! I > 80A ! 3 ms ! GLC ! Turns off ! !

! (OC) ! rential! + or - ! + or - ! GCR ! voltage ! !

! (IDG) ! current! 0.8A ! 0.3 ms ! ! regulator. ! !

! ! from ! ! ! ! 28VDC is pro-! !

! ! 6 hole ! ! ! ! vided by TDC ! !

! ! CTA ! ! ! ! AC SENSOR to ! !

! ! ! ! ! ! fire trip GCU ! !

! ! ! ! ! ! input ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! GLC fai- ! Indivi-! GLC status! 250 ms !LOCKS! ! !

! -lure (IDG! -dual ! ON and I ! + or - ! OUT ! ! !

! and APU ! CTA ! I > or = ! 50 ms ! BTC ! ! !

! GEN) ! current! 25A ! ! ! ! !

! ! GLC ! + or - 5A ! ! ! ! !

! ! status ! with PRR ! ! ! ! !

! ! ! OFF ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! APU ready ! Signal ! Absence of! None ! GLC ! Generator ! !

! (APU GEN) ! from ! signal ! ! ! excitation ! !

! ! elec- ! ! ! ! is cut off ! !

! ! tronic ! ! ! ! through signal! !

! ! control! ! ! ! at frequency ! !

! ! unit of! ! ! ! below 325Hz. ! !

! ! APU ! ! ! !.Oil over temp ! !

! ! ! ! ! ! 185 deg. C ! !

! ! ! ! ! ! + or - 5 deg.C! !

! ! ! ! ! !.Speed 95 per- ! !

! ! ! ! ! ! cent Nn signal! !

! ! ! ! ! ! from ECB ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Oil Over ! Oil out! 185 plus ! None ! ! IDG fault ! !

!Temperature! tempe- ! or minus ! ! ! indication ! !

! (OOT) ! rature ! 5 deg.C ! ! ! ! !

! (IDG) ! bulb ! ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Open Cir- !4 cables! >9A ! 37.5 ms ! GCR ! If either CT, ! !

! cuit (OCT)!from ge-! average ! + or - ! GLC ! except 6 h CT,! !

! !nerator ! current ! 5 ms ! BTC ! opens while ! !

! !CT and 4! ! ! ! loaded reclose! !

! !cables ! ! ! ! BTC and if ! !

! !from ! ! ! ! line CT opens ! !

! !line CT ! ! ! ! before closing! !

! (IDG and ! ! ! ! ! into load, ! !

! APU GEN) ! ! ! ! ! lockout BTC ! !

! ! ! ! ! ! open ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! Rotor dio-! Current! Function ! 3 s ! GCR ! Turns off vol-! !

! de short ! and ! of DC ex- ! + or - ! and ! tage regulator! !

! circuit ! voltage! citer vol-! 0.5 s ! PR ! ! !

! sensing ! exciter! tage Vs ! ! ! ! !

! ! field ! Generator ! ! ! ! !

! (IDG and ! ! load ! ! ! ! !

! APU GEN) ! ! current ! ! ! ! !

!-----------!--------!-----------!-----------!-----!---------------!----------!

! ! ! ! ! ! ! !

! Generator !.Closed ! ! !.GCR !.GLC will close! !

! control ! ! ! !close! when voltage ! !

! switch ! ! ! ! ! frequency and ! !

! ! ! ! ! ! phase sequence! !

! ! ! ! ! ! are within ! !

! ! ! ! ! ! limits ! !

! !.Open ! ! !.GCR !.Turns off vol-! !

! ! ! ! ! trip! tage regulator! !

! ! ! ! ! GLC ! ! !

! ! ! ! ! open! ! !

-------------------------------------------------------------------------------

(6) Generator control and protection functions
The following control or fault signals cause generator shutdown or de-energization:

No controlled Shutdown recognized upon power-up of the control unit
Overvoltage Fault
Undervoltage 1 Fault
Undervoltage 2 Fault
Overfrequency 1 Fault
Overfrequency 2 Fault
Overfrequency 3 Fault
Underfrequency 1 Fault
Underfrequency 2 Fault
Underspeed
Shorted Rotating Diode (PMG to chassis short) Fault
Open Cable Fault
Differential Protection Fault
Overcurrent Fault
Delta Overcurrent Fault
Phase Sequence Fault with the Power Ready Relay "absent"
Servo Valve Deterioration Fault
Disconnect Trip Fault
Welded GLC Fault
GLC Control Circuit Fault
Shorted/Open PMG Fault with the Power Ready Relay "absent"
Pin Programming Error detected on GCU power-up.
The generator shall be "reset" when the protective faults (identified above) are still not present and one of the following occurs:
Cold Start (which is defined as POWER-UP RESET or the application of 28 volts to the control unit) occurs,
Generator Control Switch (GCS) is toggled (OFF to ON).
The following functions shall be limited to a total of 2 resets after which a cold start will be requuired for reset:
Overvoltage Fault
Overfrequency 2 Fault
Differential Protection Fault
Overcurrent 2 Fault
Servo Valve Deterioration Fault
Welded GLC Fault

GLC Control Circuit Fault
A table listing all these functions is shown below.
GCU DETECTION:

-------------------------------------------------------------------------------

! FUNCTION ! SENSING ! THRESHOLD ! TIME DELAY ! TRIPS !

!------------------!-------------!--------------!-----------------!-----------!

! Overvoltage (OV) ! Highest POR ! 130 +/- 1.5V ! Inverse Curve ! GCR, PRR !

! ! phase ! ! TD (max) ! !

!------------------!-------------!--------------!-----------------!-----------!

! Undervoltage ! Lowest POR ! ! ! GCR, PRR !

! (UV1) ! phase !101.5 +/- 1.5V! 4.5 seconds ! !

! ! !4V Hysteresis ! (max) (UV1) ! !

! (UV2) ! ! 68 +/- 1.5V ! 160 milliseconds! !

! ! !4V Hysteresis ! (max) ! !

!------------------!-------------!--------------!-----------------!-----------!

! Overfrequency ! ! ! ! GCR, PRR, !

! (OF1) ! POR equiv ! 435 +/- 1Hz ! 4.0 seconds ! SVS !

! ! (PMG) !4Hz Hysteresis! (max) ! !

! (OF2) ! POR equiv ! 452 +/- 1Hz ! 160 milliseconds! !

! ! (PMG) !4Hz Hysteresis! (max) ! !

! (OF3) ! POR equiv ! 457 +/- 2Hz ! 10 milliseconds ! !

! ! (PMG) ! ! (max) ! !

!------------------!-------------!--------------!-----------------!-----------!

! Underfrequency ! ! ! ! GCR, PRR, !

! (UF1) ! POR equiv ! 361 +/- 1Hz ! 4.0 seconds ! SVS !

! ! (PMG) !4Hz Hysteresis! (max) ! !

! (UF2) ! POR equiv ! 343 +/- 1Hz ! 160 milliseconds! !

! ! (PMG) !4Hz Hysteresis! (max) ! !

!------------------!-------------!--------------!-----------------!-----------!

! Underspeed (US) ! Engine speed! see paragraph! see paragraph ! PRR !

! IDG ! for IDG ! 6.5 for the ! 6.5 for the ! !

! ! (ARINC 429) ! A320 engines ! A320 engines ! !

!------------------!-------------!--------------!-----------------!-----------!

! Shorted Rotating !Exciter Field! > 175VDC ! 3 seconds (max) ! GCR, PRR, !

! Diode/PMG to ! Voltage ! ! ! SVS !

! Chassis Short ! ! ! ! !

!------------------!-------------!--------------!-----------------!-----------!

! Open Cable (OPC) ! Differential! 80 +/- 8 Amps! 3 seconds (max) ! GCR, PRR !

! ! Current from! ! ! !

! ! 6 hole, 2 ! ! ! !

! ! wire CTA ! ! ! !

!------------------!-------------!--------------!-----------------!-----------!

! Differential ! Gen & Line !50 +/- 10 Amps! 60 milliseconds ! GCR, PRR !

! Protection (DP) ! CT delta for! ! (max) ! !

! ! each phase ! ! ! !

! ! measurement ! ! ! !

!------------------!-------------!--------------!-----------------!-----------!

! Overcurrent (OC) ! Generator ! Imax + 15A ! Inverse Curve TD!BTC Lockout!

! ! CTs ! (min) ! (min) 60 +10,-0 ! GCR, PRR !

! ! ! ! milliseconds ! !

!------------------!-------------!--------------!-----------------!-----------!

!Delta Overcurrent ! Generator ! Delta I>75A ! Inverse Curve TD!BTC Lockout!

!(DOC) ! CTs ! (min) ! (min) ! GCR, PRR !

!------------------!-------------!--------------!-----------------!-----------!

! Phase Sequence ! POR ! ABCN ! 40 milliseconds ! GCR !

! (PSEQ) ! ! ! (max) ! !

!------------------!-------------!--------------!-----------------!-----------!

! Servo Valve ! POR equiv ! Modulation of! 2.0 seconds ! GCR, PRR, !

! Deterioration ! (PMG) ! +/- 5Hz about! (max) ! SVS !

! (SV) ! ! frequency ref! ! !

!------------------!-------------!--------------!-----------------!-----------!

! Manuel Disconnect! Discrete ! Discrete ! 40 milliseconds ! GCR, PRR, !

! (DISC) ! Switch ! Input ! (max) ! SVS !

!------------------!-------------!--------------!-----------------!-----------!

! Fire Switch ! Discrete ! Discrete ! 40 milliseconds ! GCR, PRR, !

! (FIRE) ! Switch ! Input ! (max) ! SVS !

!------------------!-------------!--------------!-----------------!-----------!

! GLC failure ! Generator ! Generator ! 160 milliseconds! GCR, BTC !

! (GLFC) ! current ! current > ! (max) ! Lockout !

! ! (after QLC ! 25 +/- 5 Amps! ! !

! ! tripped) ! ! ! !

!------------------!-------------!--------------!-----------------!-----------!

! GLC control ! Line !Line Contactor! 300 milliseconds! GCR, PRR !

! circuit failure ! Contactor ! Status ! (max) ! !

! (GLCCF) ! !disagrees with! ! !

! ! ! contactor ! ! !

! ! ! "drive" ! ! !

! ! ! command ! ! !

!------------------!-------------!--------------!-----------------!-----------!

! Shorted/Open PMG ! PMG ! Open Phase or! 4.2 seconds ! GCR, SVS !

! (SOPMG) ! !Phase to Phase! (max) ! !

! ! ! Short ! ! !

!------------------!-------------!--------------!-----------------!-----------!

! Pin Programming !Pin configu- ! N/A ! N/A ! SVS, PRR, !

! Error !ration and/or! ! ! GCR on !

! !parity error ! ! ! Coldstart !

-------------------------------------------------------------------------------

(7) Control of the various indications (warnings and annunciators)
The GCU controls the warnings and annunciators related to the IDG channel.

Generator FAULT comes on when the protections come into operation (PR opening)
Generator FAULT also comes on:
for the main generators whenever the GLC is open,
for the APU generator whenever the GLC is open or the EPC opens with the APU ready.
Galley FAULT when an overload is detected
IDG FAULT for a low pressure or high temperature of the cooling and lubrication oil system.

(8) Control of the various indications (warnings and annunciators)
The GCU controls the warnings and annunciators related to the IDG channel.

Generator FAULT comes on when the protections come into operation (PR opening)
Generator FAULT also comes on when the GLC is open
Galley FAULT when an overload is detected
IDG FAULT for a low pressure or high temperature of the cooling and lubrication oil system.

(9) System self-monitoring and test function (BITE)
This function can be divided into three different parts:

Test and analysis after generator tripping,
Passive fault detection,
Maintenance test.

(a) Test and analysis after generator tripping
When a generator has tripped (active failure), the GCU

Identifies the protection which has caused the tripping (over-frequency, differential protection, etc...),
Analyses the conditions in which the tripping has occurred,
Then, determines the origin of the fault (GCU wiring or peripherals).

(b) Passive fault detection
Certain passive fault can affect the system operation, but the generator continues to work.
The GCU permanently monitors the majority of the circuits concerned.
When detecting a fault, the GCU determines the origin.

(c) Maintenance test
It can only be performed on the ground, with IDGs shut down.
It completes to a certain extent, the above described monitorings.
The test consists in exciting (stimuli) the circuits concerned and analysing the response.
It is controlled:

Either automatically at each GPCU Power Up,
Or manually by means of a discrete signal provided by the CFDIU to the GPCU.

All the data relating to these tests are stored in a coded form in the non volatile memory of the GCU (62 failures capacity). Only the faults of the last 7 flights are kept in the non volatile memory.
The architecture of data transmissions is described more in detail in the GPCU functions (Ref. AMM D/O 24-41-00-00).

(d) Electrical Generation Interface Unit (EGIU)
The main function of this unit is to provide main electrical parameters to the SDACS via ARINC 429 data links.
Two identical EGIU's are used per aircraft. One consists of 2 isolated channels:

Electrical Generation Interface Unit - Schematic Diagram ** ON A/C NOT FOR ALL

Channel 1 is allocated to IDG1 or IDG2,
Channel 2 is allocated to APU Generator or External Power (EXT PWR).

The information provided to the SDACs is as follows:

POR voltage (phase A),
Load (phase A),
Line Frequency (phase A),
Oil Inlet/Outlet Temperature,
Overload,
Generator Fault,
IDG Disconnect Status,
IDG Low Oil Pressure,
External Power available,
External Power ON.

Analog and discrete input parameters are listed below:
Channel 1: Analog and Discrete Input Parameters

-------------------------------------------------------------------------------

! PARAMETER DEFINITION !IDG1!IDG2! STATE ! COMMENTS !

!-----------------------------!----!----!-------------!-----------------------!

! POR VOLTAGE 115VAC, 400Hz ! X ! X ! ! Parameter for defini- !

! (PHASE A) ! ! ! ! tion of AC voltage !

! ! ! ! ! and frequency !

!-----------------------------!----!----!-------------!-----------------------!

! AC LOAD ! X ! X ! ! !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG OIL INLET TEMPERATURE ! X ! X ! ! !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG OIL OUTLET TEMPERATURE ! X ! X ! ! !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! OVERLOAD WARNING ! X ! X ! Ground when ! !

! ! ! ! overload ! !

!-----------------------------!----!----!-------------!-----------------------!

! GENERATOR FAULT ! X ! X ! 28VDC when ! !

! ! ! ! FAULT ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG DISC. STATUS ! X ! X ! Ground when ! !

! ! ! ! DISC ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG DISC P/BSW POS ! X ! X ! Ground when ! From P/BSW contact !

! ! ! ! ON ! relay !

!-----------------------------!----!----!-------------!-----------------------!

! IDG OIL LOW PRESSURE ! X ! X ! Ground when ! From IDG low pressure !

! ! ! ! low pressure! switch !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! GEN P/BSW POSITION ! X ! X ! 28VDC when ! From GCU TR source !

! ! ! ! ON ! (through PR) !

-------------------------------------------------------------------------------

Channel 2: Analog and Discrete Input Parameters

-------------------------------------------------------------------------------

! PARAMETER DEFINITION ! EXT! APU! STATE ! COMMENTS !

! ! PWR! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! POR VOLTAGE 115VAC 400Hz ! X ! X ! ! Parameter for defini- !

! (PHASE A) ! ! ! ! tion of AC voltage !

! ! ! ! ! and frequency !

!-----------------------------!----!----!-------------!-----------------------!

! AC LOAD ! ! X ! ! !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! OVERLOAD WARNING ! ! X ! Ground when ! !

! ! ! ! overload ! !

!-----------------------------!----!----!-------------!-----------------------!

! GENERATOR FAULT ! ! X ! 28VDC when ! From aircraft 28VDC !

! ! ! ! FAULT ! (through power ready) !

!-----------------------------!----!----!-------------!-----------------------!

! GEN P/BSW POSITIOM ! ! X ! 28VDC when ! From GCU TR source !

! ! ! ! ON ! (through PR) !

!-----------------------------!----!----!-------------!-----------------------!

! EXT PWR AVAILABLE ! X ! ! 28VDC when ! !

! ! ! ! available ! !

!-----------------------------!----!----!-------------!-----------------------!

! Class II FAILURE ! X ! ! Ground when ! !

! ! ! ! message ! !

!-----------------------------!----!----!-------------!-----------------------!

! EXT PWR ON ! X ! ! Ground when ! !

! ! ! ! ON ! !

-------------------------------------------------------------------------------

Channel 2: Flip-Flop Circuit

-------------------------------------------------------------------------------

! INPUT ! STATE ! COMMENTS !

!---------------------------------------!-------------!-----------------------!

! 28VDC VIA EXT PWR P/BSW ! 28VDC when ! !

! ! P/BSW ON ! !

-------------------------------------------------------------------------------

Each EGIU includes a one shot circuit controlled by EXT PWR pushbutton switch allowing to latch the EPC auxiliary relay. This device is located on channel 2 of EGIU.

Flip-Flop Circuit - Block Diagram ** ON A/C NOT FOR ALL

The supply of each channel of the unit is provided:

either by 28V back-up (from busbar 3PP),
or by 28VDC delivered by the associated control unit (GCU or GPCU).

A 5VDC supply is provided to the FAULT legend of the GEN pushbutton switches.

(10) System self-monitoring and test function (BITE)
This function can be divided into three different parts:

Test and analysis after generator tripping,
Passive fault detection,
Maintenance BITE.

(a) Test and analysis after generator tripping
When a generator has tripped (active failure), the GCU

Identifies the protection which has caused the tripping (over-frequency, differential protection, etc...),
Analyses the conditions in which the tripping has occurred,
Then, determines the origin of the fault (GCU wiring or peripherals).

(c) Maintenance BITE
The maintenance BITE is intended to operate with the relevant generator not running. The maintenance BITE is executed only, upon command from the GAPCU. The GAPCU only requests the maintenance BITE if requested by the Centralized Fault Display Interface Unit (CFDIU).
For more details, refer to 24-41-00 Para. BITE Test.

(d) Communication between the GCU and the SDAC
The other functions on the GCU is to provide main electrical parameters to the SDACS via ARINC 429 data links.
The infomation provided to the SDACs is as follows:

POR voltage (phase A),
Load (phase A),
Line Frequency (phase A),
Oil Inlet/Outlet Temperature,
Overload,
Generator Fault,
IDG Disconnect Status,

IDG Low Oil Pressure.
Analog and discrete input parameters are listed below:

-------------------------------------------------------------------------------

! PARAMETER DEFINITION !IDG1!IDG2! STATE ! COMMENTS !

!-----------------------------!----!----!-------------!-----------------------!

! POR VOLTAGE 115VAC, 400Hz ! X ! X ! ! Parameter for defini- !

! (PHASE A) ! ! ! ! tion of AC voltage !

! ! ! ! ! and frequency !

!-----------------------------!----!----!-------------!-----------------------!

! AC LOAD ! X ! X ! ! !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG OIL INLET TEMPERATURE ! X ! X ! ! !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG OIL OUTLET TEMPERATURE ! X ! X ! ! !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! OVERLOAD WARNING ! X ! X ! Ground when ! !

! ! ! ! overload ! !

!-----------------------------!----!----!-------------!-----------------------!

! GENERATOR FAULT ! X ! X ! 28VDC when ! !

! ! ! ! FAULT ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG DISC. STATUS ! X ! X ! Ground when ! !

! ! ! ! DISC ! !

!-----------------------------!----!----!-------------!-----------------------!

! IDG DISC P/BSW POS ! X ! X ! Ground when ! From P/BSW contact !

! ! ! ! ON ! relay !

!-----------------------------!----!----!-------------!-----------------------!

! IDG OIL LOW PRESSURE ! X ! X ! Ground when ! From IDG low pressure !

! ! ! ! low pressure! switch !

! ! ! ! ! !

!-----------------------------!----!----!-------------!-----------------------!

! GEN P/BSW POSITION ! X ! X ! 28VDC when ! From GCU TR source !

! ! ! ! ON ! (through PR) !

-------------------------------------------------------------------------------

B. System Data Acquisition Concentrator (SDAC) Communications

SDAC Communication - Block Diagram ** ON A/C NOT FOR ALL

Each EGIU channel interfaces with each SDAC via a single ARINC 429 data bus.
The parameters are displayed on the ECAM system.

SDAC Communication - Block Diagram ** ON A/C NOT FOR ALL

Each GCU channel interfaces with each SDAC via a single ARINC 429 data bus.
The parameters are displayed on the ECAM system.

(1) Table of main digital signals received and sent out by the SDAC 1(2)

-------------------------------------------------------------------------------

! CHANNEL 1 !

!-----------------------------------------------------------------------------!

! OUT ! SDI ! !FORMAT!REFRESH! No.OF!CODING! ! ! SOURCE !

!LABEL!GEN1!GEN2! PARAMETER !(BNR ! RATE !SIGNI-!RANGE !RESOL!UNIT! ORIGIN !

! ! ! ! DEFINITION ! or ! (MS) !FICANT! MIN/ ! ! ! !

! ! ! ! ! BCD) !MIN/MAX! BITS ! MAX ! ! ! !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 070 ! 01 ! 10 ! AC FREQUEN-! BNR !250/500! 9 ! 0/512! 1Hz ! Hz ! From !

! ! ! ! CY Ph A ! ! ! ! ! ! ! 115VAC !

! ! ! ! ! ! ! ! ! ! ! 400Hz !

! ! ! ! ! ! ! ! ! ! ! INPUT !

! ! ! ! ! ! ! ! ! ! ! GCU 1 !

! ! ! ! ! ! ! ! ! ! ! GCU 2 !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 072 ! 01 ! 10 ! AC VOLTAGE ! BNR !250/500! 8 ! 0/256! 1V ! V ! From !

! ! ! ! Ph A ! ! ! ! ! ! ! 115VAC !

! ! ! ! ! ! ! ! ! ! ! 400Hz !

! ! ! ! ! ! ! ! ! ! ! INPUT !

! ! ! ! ! ! ! ! ! ! ! GCU 1 !

! ! ! ! ! ! ! ! ! ! ! GCU 2 !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 077 ! 01 ! 10 ! AC LOAD ! BNR !250/500! 8 ! 0/256! 1per! per! GCU 1 !

! ! ! ! ! ! ! ! ! cent!cent! GCU 2 !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 105 ! 01 ! 10 ! IDG OIL ! BNR !250/500! 8 ! -256 ! 1 !deg.! GCU 1 !

! ! ! ! INLET TEMP ! ! ! ! / !deg.C! C ! GCU 2 !

! ! ! ! ! ! ! ! +256 ! ! ! !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 106 ! 01 ! 10 ! IDG OIL ! BNR !250/500! 8 ! -256 ! 1 !deg.! GCU 1 !

! ! ! ! OUTLET TEMP! ! ! ! / !deg.C! C ! GCU 2 !

! ! ! ! ! ! ! ! +256 ! ! ! !

-------------------------------------------------------------------------------

! CHANNEL 2 !

!-----------------------------------------------------------------------------!

! OUT ! SDI ! !FORMAT!REFRESH! No.OF!CODING! ! ! SOURCE !

!LABEL!APU !EXT ! PARAMETER !(BNR ! RATE !SIGNI-!RANGE !RESOL!UNIT! ORIGIN !

! !GEN !PWR ! DEFINITION ! or ! (MS) !FICANT! MIN/ ! ! ! !

! ! ! ! ! BCD) !MIN/MAX! BITS ! MAX ! ! ! !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 071 ! 01 ! !APU GEN FREQ! BNR !250/500! 9 ! 0/512! 1Hz ! Hz !APU GCU !

! ! ! ! ! ! ! ! ! ! ! !

! ! ! 10 !EXT PWR FREQ! ! ! ! ! ! !GPCU !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 075 ! 01 ! !APU GEN ! BNR !250/500! 8 ! 0/256! 1V ! V !APU GCU !

! ! ! !VOLTAGE ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! !

! ! ! 10 !EXT PWR ! ! ! ! ! ! !GPCU !

! ! ! !VOLTAGE ! ! ! ! ! ! ! !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 100 ! 00 ! ! AC LOAD ! BNR !250/500! 8 ! 0/256! 1per! per!APU GCU !

! ! ! ! ! ! ! ! cent!cent! !

-------------------------------------------------------------------------------

! CHANNEL 1 !

!-----------------------------------------------------------------------------!

! OUT ! ! SDI ! !REFRESH! ! ! SOURCE !

!LABEL! BIT!GEN1!GEN2! PARAMETER ! RATE ! STATE 0 ! STATE 1 ! ORIGIN !

! ! No.! ! ! DEFINITION! (MS) ! ! ! !

! ! ! ! ! !MIN/MAX! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 11 ! 01 ! 10 ! OVERLOAD !250/500!no warning! warning ! !

! ! ! ! ! WARNING ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 12 ! 01 ! 10 ! GENERATOR !250/500! no fault ! fault ! !

! ! ! ! ! FAULT ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 13 ! 01 ! 10 ! IDG DIS- !250/500! not disc ! disc ! !

! ! ! ! ! CONNECT ! ! ! ! !

! ! ! ! ! STATUS ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 14 ! 01 ! 10 ! IDG DIS- !250/500! P/BSW OFF! P/BSW ON ! !

! ! ! ! ! CONNECT ! ! ! ! !

! ! ! ! ! P/B POS ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 17 ! 01 ! 10 ! IDG OIL !250/500! no over- ! overheat ! From IDG !

! ! ! ! ! OUTLET ! ! heat ! ! OUTLET TEMP !

! ! ! ! ! OVERHEAT ! ! ! ! Input parame-!

! ! ! ! ! ! ! ! ! ter with !

! ! ! ! ! ! ! ! ! threshold !

! ! ! ! ! ! ! ! !185 deg.C plus!

! ! ! ! ! ! ! ! ! or minus !

! ! ! ! ! ! ! ! ! 5 deg.C !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 18 ! 01 ! 10 ! IDG OIL !250/500! low pres-! normal ! !

! ! ! ! ! LOW PRES- ! ! sure ! pressure ! !

! ! ! ! ! SURE ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 19 ! 01 ! 10 ! GEN P/BSW !250/500! P/BSW OFF! P/BSW ON ! !

! ! ! ! ! POSITION ! ! ! ! !

-------------------------------------------------------------------------------

! CHANNEL 2 !

!-----------------------------------------------------------------------------!

! OUT ! ! SDI ! !REFRESH! ! ! SOURCE !

!LABEL! BIT!GEN3! EXT! PARAMETER ! RATE ! STATE 0 ! STATE 1 ! ORIGIN !

! ! No.! ! PWR! DEFINITION! (MS) ! ! ! !

! ! ! ! ! !MIN/MAX! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 052 ! 11 ! 01 ! ! OVERLOAD !250/500!no warning! warning ! !

! ! ! ! ! WARNING ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 052 ! 12 ! 01 ! ! GENERATOR !250/500! no fault ! fault ! !

! ! ! ! ! FAULT ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 052 ! 14 ! 01 ! ! GEN P/BSW !250/500! P/BSW OFF! P/BSW ON ! !

! ! ! ! ! POSITION ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 052 ! 12 ! ! 10 ! EXT PWR !250/500! not avai-! available! !

! ! ! ! ! AVAILABLE ! ! lable ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 052 ! 13 ! ! 10 ! EXT PWR ON!250/500! OFF ! ON ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 052 ! 15 ! ! 10 ! CLASS II !250/500!no failure! failure ! Actuated by !

! ! ! ! ! FAILURE ! ! ! ! GPCU BITE !

! ! ! ! ! ! ! ! ! Message !

! ! ! ! ! ! ! ! ! Discrete !

NOTE: For some more information: see ATA Ref. 31-54-00.

(2) Table of main digital signals received and sent out by the SDAC 1(2)

-------------------------------------------------------------------------------

! CHANNEL 1 !

!-----------------------------------------------------------------------------!

! OUT ! SDI ! !FORMAT!REFRESH! No.OF!CODING! ! ! SOURCE !

!LABEL!GEN1!GEN2! PARAMETER !(BNR ! RATE !SIGNI-!RANGE !RESOL!UNIT! ORIGIN !

! ! ! ! DEFINITION ! or ! (MS) !FICANT! MIN/ ! ! ! !

! ! ! ! ! BCD) !MIN/MAX! BITS ! MAX ! ! ! !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 070 ! 01 ! 10 ! AC FREQUEN-! BNR !250/500! 9 ! 0/512! 1Hz ! Hz ! From !

! ! ! ! CY Ph A ! ! ! ! ! ! ! 115VAC !

! ! ! ! ! ! ! ! ! ! ! 400Hz !

! ! ! ! ! ! ! ! ! ! ! INPUT !

! ! ! ! ! ! ! ! ! ! ! GCU 1 !

! ! ! ! ! ! ! ! ! ! ! GCU 2 !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 072 ! 01 ! 10 ! AC VOLTAGE ! BNR !250/500! 8 ! 0/256! 1V ! V ! From !

! ! ! ! Ph A ! ! ! ! ! ! ! 115VAC !

! ! ! ! ! ! ! ! ! ! ! 400Hz !

! ! ! ! ! ! ! ! ! ! ! INPUT !

! ! ! ! ! ! ! ! ! ! ! GCU 1 !

! ! ! ! ! ! ! ! ! ! ! GCU 2 !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 077 ! 01 ! 10 ! AC LOAD ! BNR !250/500! 8 ! 0/256! 1per! per! GCU 1 !

! ! ! ! ! ! ! ! ! cent!cent! GCU 2 !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 105 ! 01 ! 10 ! IDG OIL ! BNR !250/500! 8 ! -256 ! 1 !deg.! GCU 1 !

! ! ! ! INLET TEMP ! ! ! ! / !deg.C! C ! GCU 2 !

! ! ! ! ! ! ! ! +256 ! ! ! !

!-----!----!----!------------!------!-------!------!------!-----!----!--------!

! 106 ! 01 ! 10 ! IDG OIL ! BNR !250/500! 8 ! -256 ! 1 !deg.! GCU 1 !

! ! ! ! OUTLET TEMP! ! ! ! / !deg.C! C ! GCU 2 !

! ! ! ! ! ! ! ! +256 ! ! ! !

-------------------------------------------------------------------------------

! CHANNEL 1 !

!-----------------------------------------------------------------------------!

! OUT ! ! SDI ! !REFRESH! ! ! SOURCE !

!LABEL! BIT!GEN1!GEN2! PARAMETER ! RATE ! STATE 0 ! STATE 1 ! ORIGIN !

! ! No.! ! ! DEFINITION! (MS) ! ! ! !

! ! ! ! ! !MIN/MAX! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 11 ! 01 ! 10 ! OVERLOAD !250/500!no warning! warning ! !

! ! ! ! ! WARNING ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 12 ! 01 ! 10 ! GENERATOR !250/500! no fault ! fault ! !

! ! ! ! ! FAULT ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 13 ! 01 ! 10 ! IDG DIS- !250/500! not disc ! disc ! !

! ! ! ! ! CONNECT ! ! ! ! !

! ! ! ! ! STATUS ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 14 ! 01 ! 10 ! IDG DIS- !250/500! P/BSW OFF! P/BSW ON ! !

! ! ! ! ! CONNECT ! ! ! ! !

! ! ! ! ! P/B POS ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 17 ! 01 ! 10 ! IDG OIL !250/500! no over- ! overheat ! From IDG !

! ! ! ! ! OUTLET ! ! heat ! ! OUTLET TEMP !

! ! ! ! ! OVERHEAT ! ! ! ! Input parame-!

! ! ! ! ! ! ! ! ! ter with !

! ! ! ! ! ! ! ! ! threshold !

! ! ! ! ! ! ! ! !185 deg.C plus!

! ! ! ! ! ! ! ! ! or minus !

! ! ! ! ! ! ! ! ! 5 deg.C !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 18 ! 01 ! 10 ! IDG OIL !250/500! low pres-! normal ! !

! ! ! ! ! LOW PRES- ! ! sure ! pressure ! !

! ! ! ! ! SURE ! ! ! ! !

!-----!----!----!----!-----------!-------!----------!----------!--------------!

! 050 ! 19 ! 01 ! 10 ! GEN P/BSW !250/500! P/BSW OFF! P/BSW ON ! !

! ! ! ! ! POSITION ! ! ! ! !

(3) Table of main discrete signals received and sent out by the SDAC1(2)

-------------------------------------------------------------------------------

| PARAMETER LIST PARAMETER CHARACTERISTICS (NUMERIC) |

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

! 002 00! BUS TIE ! ! ! ! 21 ! ! ! ! 10XU !

! ! P/B OFF ! ! ! ! ! ! ! ! !

! 002 00! BUS TIE ! ! ! ! 21 ! ! ! ! 10XU !

! ! P/B ON ! ! ! ! ! ! ! ! !

! 002 01!GEN1 LINE ! ! ! ! 14 ! ! ! ! 9XU1 !

! !CNTOR ON ! ! ! ! ! ! ! ! !

! 002 01!GEN1 LINE ! ! ! ! 14 ! ! ! ! 9XU1 !

! !CNTOR OFF ! ! ! ! ! ! ! ! !

! 002 01! TRANSFER ! ! ! ! 15 ! ! ! ! 11XU1 !

! !CNTOR1 ON ! ! ! ! ! ! ! ! !

! 002 01! TRANSFER ! ! ! ! 15 ! ! ! ! 11XU1 !

! !CNTOR1 OFF! ! ! ! ! ! ! ! !

! 002 10!GEN2 LINE ! ! ! ! 14 ! ! ! ! 9XU2 !

! !CNTOR ON ! ! ! ! ! ! ! ! !

! 002 10!GEN2 LINE ! ! ! ! 14 ! ! ! ! 9XU2 !

! !CNTOR OFF ! ! ! ! ! ! ! ! !

! 002 10! TRANSFER ! ! ! ! 15 ! ! ! ! 11XU2 !

! !CNTOR2 ON ! ! ! ! ! ! ! ! !

! 002 10! TRANSFER ! ! ! ! 15 ! ! ! ! 11XU2 !

! !CNTOR2 OFF! ! ! ! ! ! ! ! !

NOTE: For some more information: see ATA Ref. 31-54-00.

C. Power Contactor

(1) Technology
The contactors are made up of a base with the power circuit connector terminals and a removable assembly mainly consisting of the motor, power contacts, auxiliary contacts and connector.
It is possible to remove a contactor without removing the base to which power circuits are connected.

(2) Technology
The contactors are made up of a removable assembly which mainly consists of the motor, power contacts, auxiliary contacts and connector.
The contactors are installed on a module or a base to which the power circuits are connected.
It is possible to remove a contactor without removing the module or the base.

(3) Characteristics of main contacts

(a) Three pole contactors: 2 types (260 A or 60 A)
Nominal current

260 A,
60 A.

Overload at nominal voltage

1.5 x In for 5 minutes
2 x In for 1 minute.

(b) Single pole contactors: 3 types (100 A or 200 A or 300 A)
Nominal current

100 A,
200 A,
300 A.

Overload

100 A or 200 A:
1.5XIn for 5 minutes
2XIn for 1 minute
5XIn for 1 second (only for 200 A contactors).
300 A: in normal operation one cycle has an inrush current of 650 A to 950 A and cut off current of 150 A to 300 A (APU start contactor).

D. TDC AC Sensor
If an open cable condition occurs with a current of more than 80A, after a 3 seconds delay, the TDC AC sensor 50XU1 (50XU2) supplies a 28VDC signal to the GPCU and to the fire trip GCU1 (GCU2) input.
The GCU1 (GCU2) does not energize its related GLC1 (GLC2) contactor.

E. Lightning Protection Module
The lightning protection modules (19XU1, 19XU2) protect the equipment supplied by the feeders of the IDGs (115V/400Hz, three-phase) against the lightning strikes.

F. Current Transformer (CT)

AC Main Generation - Component Location ** ON A/C NOT FOR ALL

Current Transformers - Block Diagram ** ON A/C NOT FOR ALL

There are two CTs per AC main generation channel:

One CT is built into the IDG generator,
One six-hole CT is installed upstream of the generator line contactor.

AC Main Generation - Component Location ** ON A/C NOT FOR ALL

Current Transformers - Block Diagram ** ON A/C NOT FOR ALL

There are three CTs per AC main generation channel:

One CT is built into the IDG generator,
One three-hole CT is installed upstream of the generator line contactor,
One six-hole CT is installed upstream of the three-hole CT.

(1) Functions

(a) Generator CT
The generator CT is used for differential and overcurrent protections (Ref. Para. 4.A.(2) Generator control and protection functions).

(b) Six-hole CT
The six-hole CT contains six toroidal transformers, one for each of the parallel power feeder cables. The six-hole CT is connected in electrical opposition to the CT of the IDG generator.
This CT is used for differential and open cable protections (Ref. Para. 4.A.(2) Generator control and protection functions).

(2) Functions

(a) Generator CT
The generator CT is used for differential and overcurrent protections (Ref. Para. 4.A.(4) Generator control and protection functions).

(b) Six-hole CT
The six-hole CT contains six toroidal transformers, one for each of the parallel power feeder cables. The six-hole CT is connected in electrical opposition to the CT of the IDG generator.
This CT is used for open cable protections (Ref. Para. 4.A.(4) Generator control and protection functions).

** ON A/C NOT FOR ALL

5. Operation/Control and Indicating

A. Generator Control
Controls and indications for each generator are located on the overhead panel in the cockpit. The signals to and from the indicators and controls transit by the GCU.
A general view of AC main generation channel 1 is shown on

AC Main Generation Channel 1 - Schematic Diagram ** ON A/C NOT FOR ALL

Each GCU controls the opening and closing of the associated GLC.

GLC/BTC Logic - Schematic Diagram ** ON A/C NOT FOR ALL

GLC-1 Supply - Schematic Diagram ** ON A/C NOT FOR ALL

The operation of each generator is controlled by the GEN1 (2) pushbutton switch.
This pushbutton switch has two stable positions:

OFF selected, the pushbutton switch is released and the white OFF legend is on. The generator is shut down (de-energized) and the line contactor (GLC) is open,
When the pushbutton switch is pressed in, the generator is energized, its rotational speed being high enough. If the electrical parameters are correct, the line contactor closes. Then, the generator supplies its network.

When a fault is detected:

The GCU protections are activated (PR opening),
FAULT legend comes on on GEN pushbutton switch (accompanied by the single chime and MASTER CAUT light).

GEN 1 FAULT - Upper and Lower ECAM Display Unit

At the same time:

On the upper display unit of the ECAM system, an amber message is displayed,
On the lower display unit, the ELEC page is automatically displayed.

Simultaneously, the automatic transfer becomes effective:

The lost network is supplied by another power source available.

The crew has to release-out GEN pushbutton switch (white OFF legend comes on on GEN pushbutton switch).

NOTE: FAULT legend comes on on GEN pushbutton switch also when GLC is open.
When starting engine 1, GEN 1 OFF warning is displayed on the ECAM display unit if generator 1 is not on line:

GEN 1 OFF - Upper and Lower ECAM Display Unit

Similarly, when starting engine 2, GEN 2 OFF warning is displayed on the ECAM display unit if generator 2 is not in line:

GEN 2 OFF - Upper and Lower ECAM Display Unit

B. Transfer Circuit
The transfer circuit enables supply of both or either AC electrical network(s) from one of the four power sources (GEN 1, GEN 2, APU GEN, EXT PWR). This is via the transfer contactors (BTC). The BTC control is entirely automatic. It depends on the availability of these sources and the correct condition of each network. The BTC 1 closes if no interlock condition exists on GCU 1:

BTC-1 Supply - Schematic Diagram ** ON A/C NOT FOR ALL

when generator 1 is not available, in order to supply network 1 from another power source (generator 2, auxiliary generator or ground power unit),
To supply network 2 from generator 1 in case of non-availability of:
generator 2,
auxiliary generator,
and electrical ground power unit.
In case of single generator configuration, the sheddable busbars 218XP, 220XP, 210PP and 212PP are no longer available.

BTC2 control is symmetrical to BTC1

BTC-2 Supply - Schematic Diagram ** ON A/C NOT FOR ALL

GCU1 or GCU2 enables closure of BTC1 or BTC2 if:

no DP zone 2 condition,
no GLC welded failure occurred.

Networks 1 and 2 are supplied in priority order:

by the corresponding generator,
by the electrical ground power unit,
by the auxiliary generator,
or by the other generator.

NOTE: BTC's 1 and 2 can be locked out by pressing BUS TIE pushbutton switch located on ELEC overhead panel (Ref. AMM D/O 24-00-00-00). This causes both channels to be isolated.

In case of transfer impossibility or inhibition, AC BUS 1 or AC BUS 2 are lost.
The procedure to be applied in case of loss of these busbars is shown in figures.

AC BUS 1 Fault - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

AC BUS 2 Fault - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

GCU1 or GCU2 enables closure of BTC1 or BTC2 if:

no DP overcurrent or Delta Current condition,
no GLC welded failure occurred.

Networks 1 and 2 are supplied in priority order:

by the corresponding generator,
by the electrical ground power unit,
by the auxiliary generator,
or by the other generator.

NOTE: BTC's 1 and 2 can be locked out by pressing BUS TIE pushbutton switch located on ELEC overhead panel (Ref. AMM D/O 24-00-00-00). This causes both channels to be isolated.

In case of transfer impossibility or inhibition, AC BUS 1 or AC BUS 2 are lost.
The procedure to be applied in case of loss of these busbars is shown in figures.

AC BUS 1 Fault - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

AC BUS 2 Fault - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

C. Smoke Detection
In case of smoke detection, amber SMOKE legend comes on on GEN 1 LINE pushbutton switch located on cockpit overhead panel (Ref. AMM D/O 24-00-00-00).
It is accompanied by the single chime and the MASTER WARN.
Then, the crew has to follow the procedure shown in figures

Smoke Detection - Upper and Lower ECAM Display Unit

NOTE: This smoke procedure is also described in Ref. 24-24-00 since the emergency generator is used in the smoke configuration.

** ON A/C NOT FOR ALL

6. BITE Test

A. Conditions of Power-up Test Initialization

(1) How long the computer must be de-energized:

15 ms.

(2) A/C configuration:

A/C on ground and engines shutdown.

B. Progress of Power-up Test

(1) Duration:

30 ms.

(2) Cockpit repercussions directly linked to power-up test accomplishment (some other repercussions may occur depending on the A/C configuration but these can be disregarded):

None.

C. Results of Power-up Test

(1) Test pass:

ECAM ELEC page:
.Generator on line (green line) and parameters available (load, voltage and frequency).

(2) Test failed:

MASTER CAUTION light comes on and chime sounds,
ECAM warning:
.ELEC GEN 1 (2) FAULT
or
.ELEC APU GEN FAULT
ECAM ELEC page:
.Generator not on line and XX amber boxed in place of parameters (load, voltage and frequency) associated with the faulty GCU.

NOTE: To de-energize the GCU, select OFF the battery switch.

D. Description

(1) Communication with the GAPCU

Ref. 24-41-00 Para.: Communications.

(2) Detection of any failures affecting the generating channel

(Ref. Para. B.).

(3) Identification of the LRU responsible for the failure

(Ref. Para. B.).

(4) Memorization of the information pertaining to the failure in Non-Volatile Memory (NVM)

The GCU contains a NVM which is implemented on the EEPROM.
The GCU NVM stores data for faults detected by the GCU BITE.
The GCU NVM is structured as other type 1 computers (Ref. 31-32-00, CFDIU).

E. Description of the Interactive Mode Function

Ref. 24-41-00 (AC External Power Control), Para.: Description of the interactive mode function.

F. Realization of the BITE/TEST

The GCU has a test initialization and three different types of BITE:

signature evaluation/monitor,
isolation,
maintenance.

The isolation BITE has the highest priority followed by the maintenance BITE, and then the signature BITE.

(1) Initialization

The test initialization is made at power-up or when the generator pushbutton switch is cycled and the watchdog has timed out or after a maintenance BITE.

(2) Signature evaluation BITE (SBITE)

Monitoring is executed as long as the GCU is powered except when the maintenance BITE or isolation BITE has precedence.
The monitor BITE does not change the contents of any RAM used by the control and protection software. It does not change the state of any of the outputs and does not stimulate any sense circuitry.

No maintenance BITE test results in the monitor/signature BITE fault being written in the NVM.
Once a given fault has been determined an indication of the fault is written into the NVM.

(3) Fault Isolation BITE (IBITE)

In the event of a protective trip, the fault isolation software determines whether the trip is due to an external fault trip condition or to a faulty sense circuitry within the controller.

The fault isolation BITE's primary function is to identify the failed LRU after a protective trip has occurred. The protective trips are classified as any fault detected by the controller that will result in a Generator Control Relay (GCR) trip or lockout of the BTC relay. After a failure has been detected, the corresponding isolation routine is executed. The only isolation that can be executed after another isolation has been completed (without the protection latch being cleared (cold start or GCS cycled)) are Differential Protection, Disconnect, Fire trips, and unrelated faults. Whenever the "controlled shut down" flag in the NVM is not true, the Generator Control Switch (GCS) must be cycled to allow the GCR to re-close.

(4) Maintenance BITE

The maintenance BITE is intended to operate with the relevant generator not running.
The maintenance BITE is executed only upon command from the GAPCU. The GAPCU only requests the maintenance BITE if requested by the CFDIU.
For more details, refer to 24-41-00 Para. BITE Test.

[Rev.10 from 2021] 2026.04.02 06:51:58 UTC