R AC Auxiliary Generation (APU Generator GAPCU)
R Component Location
R Figure 001B (SHEET 2)

R 1EFF : 401-499, 1 24-23-00Page 7 1 1 Aug 01/05 1 1 1CES 1

 AC Auxiliary Generation (APU Generator GCU)
 Component Location
 Figure 002

 1EFF : 001-049, 051-099, 101-149, 151-199, 1 24-23-00Page 8 1201-299, 301-399, 1Aug 01/05R 1 1 1CES 1

R **ON A/C 401-499,
R -------------------------------------------------------------------------------R FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA R | | | | DOOR | REF. R -------------------------------------------------------------------------------R 2XS P/BSW-ELEC/APU GEN 35VU 210 831 24-23-00 R 3XS GLC-APU 120VU 212 831 24-23-55 R 8XS GEN-APU 310 24-23-51 R 42XS CT-AC, APU GEN 120VU 212 831 24-23-00 R 24XG GAPCU 92 VU 122 24-41-00
R The APU generator is installed in the APU compartment. It is attached to the R APU gearbox by a button hole flange.

R **ON A/C ALL
 3. System Description
__________________
 **ON A/C 001-049, 051-099, 101-105, 151-158, 201-209,
 (Ref. Fig. 003)
 **ON A/C 106-149, 159-199, 210-299, 301-399,
 (Ref. Fig. 003A)

R **ON A/C 401-499,
R (Ref. Fig. 003B)
 **ON A/C ALL
 4. Component Description
_____________________
 A. APU Generator The APU directly drives the APU generator at a nominal 24000 rpm constant speed. The APU gearbox supplies the oil for cooling and lubrication of the generator. The cooling circuit is common to the APU and the generator. The APU supplies, scavenges, drains the oil.

 The generator is a brushless oil-cooled generator with a nominal 115/200 volt, 90 KVA, 3 phase 400 Hz output. The generator includes three stages which are: - the pilot exciter, - the main exciter, - the main alternator. The operation principle is the same as that of the IDG generator (Ref. 24-21, generator section).
 NOTE : The PMG frequency for the APU generator is 1600 Hz.____
 A temperature bulb is included in the auxiliary generator. It senses the generator-oil outlet temperature. This sensor is connected to the Electronic Control Box (ECB) of the APU. Any high oil temperature causes the automatic shutdown of the APU (by the ECB). This in turn causes the APU speed to decrease to zero. 
R  **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 301-399,
 B. Generator Control Unit (GCU) The overall function of the APU GCU is selected by pin programming. The 3 GCUs are identical and interchangeable. For details concerning the description and functions of the APU GCU, refer to 24-22-00. 
R  **ON A/C 401-499, 
R R R R R R R R R R R R R  B. Ground and Auxiliary Power Unit (GAPCU) The GAPCU controls the APU generator and the external Power channels. For the APU generator channel control, the GAPCU has different functions: - voltage regulation, - control and protection of the network and the generator, - control of the various indications, - system test and self-monitoring. The GAPCU 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.

 APU Generator Configuration - Block Diagram
 Figure 003

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 APU Generator Configuration - Block Diagram
 Figure 003A

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1R APU Generator Configuration - Block Diagram R Figure 003B

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R  (1) Voltage regulation 
R  The voltage regulation is achieved by controlling the current through 
R  the exciter field. The voltage is kept at nominal value (115 VAC) at 
R  the Point of Regulation (POR). 
R  The POR is located in the electrical power centre (120VU) at the end 
R  of the generator feeder, upstream of the line contactor. 
R  The principle of operation of the voltage regulator is by constant 
R  frequency variable pulse width modulation of the voltage through the 
R  exciter field. 
R  (2) Control and protective functions 
R  The GAPCU controls the connection and disconnection of the power 
R  provided by the generator to and from the aircraft electrical system. 
R  This control is provided by means of 2 relays: 
R  - the Generator Control Relay (GCR) which controls the generator 
R  excitation, 
　
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