Triumph TR6 PI Operation Manual page 446

KEY TO ALTERNATOR WIRING DIAGRAM
- LUCAS TYPES lSACR AND 17ACR
ELECTRICAL
I
Stator windings
2
live side output diodes
3
Earth side output diodes
4 Field winding supply diodes
5 Harness loop Circuit is made when multi-socket connector is fitted and
broken when connector is removed
6 Brushes and slip rings
7
...
Field winding
8
Connection to external harness wire Alternative to item 9. Fitted to battery sensed units
9 Internal B+ connection Alternative to item 8. Fitted to machine sensed units
R3
Resistor
Restricts T2 base current supplied from 'field winding supply'
diodes
T2 Intermediate transistor
Controls T3 base current direct
R6 Resistor Restricts T3 base current supplied from 'field winding supply'
diodes
T3 Output transistor Controls field winding earth return circuit
RI and R2 Potential divider Senses battery reference voltage
ZD Zener diode Voltage sensitive component. Opposes passage of current until
breakdown voltage - approximately 8 volts - is reached.
Controls T1 base current direct
T1 Input transistor Controls T2 base current by diverting current passing through
R3 to earth when ZD is conducting
CI and R4
Capacitor and Resistor Prevents transistor overheating by providing positive feed back
circuit to ensure quick switching of transistors from 'fully on'
to 'fully off
R5 Resistor
Path for small leakage current which may pass through ZD at
high temperatures
D
Surge quench diode Connected across field winding. Protects T3 from field
winding high induced voltage surge and smooths field winding
current
C2 Condenser
Radio interference suppression
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Triumph TR6 Manual. Part No. 545277 Issue I 86.10.00 Sheet 4