H20756 H20761
Engine-Driven Generator Control Diagram  500 
24-00  Figure 3  Nov 01/74 
Page 6 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

500  APU Generator Control Diagram 
Feb 01/76  Figure 4  24-00 
Page 7 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

E.  When both No. 1 and 2 generators are supplying power to the main load buses, No. 1 and 2 GB's will be closed. Transfer buses No. 1 and 2 will be energized with bus transfer relays No. 1 and 2 both in the normal position (Fig. 5). Bus transfer switch S2 on forward overhead panel must be in the AUTO position. Should generator No. 2 stop functioning, loads supplied from the No. 2 transfer bus will be automatically transferred to the No. 1 generator. This is accomplished by energizing the alternate coil of the No. 2 bus transfer relay through normally closed contacts of No. 2 GB. A time delay permits the circuit to mechanically clear previous connections before the No. 2 bus transfer relay closes. A similar sequence takes place should generator No. 1 stop functioning instead of No. 2. Lights on the forward overhead panel P5 indicate when the buses are de-energized. Should generator No. 1 or 2 be connected to the No. 1 and 2 main load buses respectively with the bus transfer switch S2 in the OFF position, No. 2 or 1 transfer bus OFF light respectively on the overhead panel will be on, indicating that transfer buses No. 1 or 2 are de-energized.
500 
24-00 Page 8  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Nov 01/74 

H20760
500  Transfer Bus Control Diagram 
Jul 15/70  Figure 5  24-00 
Page 9 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

GENERATOR FEEDER CU-AL SPLICES - APPROVED REPAIRS
1.  General
A.  The installation of copper (Cu)/aluminum (Al) generator feeder cables requires the use of an inline splice at the transition point. The fabrication of these splices is unique and special tools are required. Three methods are provided for insulation of the splice: tape wrap, potting, or tape and sleeve. Engine splices are located above engine nacelle by the vapor barrier forward of the front wing spar (WBL 198). APU splices are located on right side outboard of APU shroud (STA 1110). Some airplanes have inline splices on the breaker end located on right outboard side of the nose wheel well (STA 259). Later airplanes have a design improvement using improved AMP inline splices on the generator end and copper-aluminum terminal lugs on the aluminum feeder cables at the breaker end of the generator feeders.
2.  Equipment and Materials (Fig. 801)
A.  Crimping tool
B.  Die set
C.  Splices
D.  Insulation method 1, tape wrap
(1)  
General purpose cleaning solvent

(2)  
Type B film: Permacel - P412, Hwy 1, New Brunswick, NJ 08903; Oak Materials Group -E125-2 or E125-3, McCaffrey St., Hoosick Falls, NY 12090; Minnesota Mining and Mfg. Co. - Scotch 3082 (no longer procurable).

(3)  
Polymide tape, Minnesota Mining and Mfg., Co. - Scotch 61 preferred, or bondable TFE fluorocarbon film - Scotch 60, 62, 63, or polymide (H-film) - Scotch X-1205, Dodge Industries - E234-2, Borden Co. - Mystic 7367

E.  Insulation method 2, potted
(1)  
Transparent Tubing, Rayclad Tubes Inc. - Thermofit TFE-R

(2)  
Potting Compound, Products Research Co. - PR1933

F.  Insulation method 3, tape and sleeve
(1)  
Items (1) and (2) same as method 1

(2)  
Heat-shrink tubing, Raychem Inc. - Thermofit PD (MS-70)

3.  Preparation
A. Determine method of insulation to be performed; if methods 2 or 3 are to be used, prepare per
6.B or 6.C, steps (1) thru (3).
B.  Select proper splice for wire sizes to be joined (Fig. 801).
C.  Strip wires to be spliced according to wire type (Fig. 802) and strip length (Fig. 801).
4.  
Deleted

5.  
Splicing (AMP Cu-Al splices)

501 
Jun 20/87  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  24-00-09 Page 801 

A.  Insert conductors into crimp barrels of splice without distorting strands having primary insulation tight against splice.
CAUTION:  FAILURE TO MATE PROPER SIDE OF SPLICE TO COPPER WIRE MAY RESULT IN SPLICE DAMAGE.
　
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