Triumph TR6 PI Operation Manual page 491

ELECTRICAL
Motor
A series-wound, four-pole, four-brush motor with a_
shaft which carries a roller clutch drive.
The armature shaft rotates in two porous bronze
bushes. The armature features a face-type moulded
commutator.
Shaft end-float is controlled at the commutator end
cover by the internal thrust washer and the position of a
Spire retaining ring fitted on the shaft extension.
A plastic brush box is riveted to the commutator end
cover. It holds four wedge-shaped brushes and captive coil
springs. The brushes are keyed to ensure correct fitting.
The field winding is four joined strips. One end is
attached to two brush flexibles, while the other is attached
to a single flexible which is earthed to the yoke.
The yoke is windowless. The yoke and commutator
end cover are secured by two through bolts which screw
into tappings provided in the drive-end bracket.
Solenoid and roller clutch drive
The starter solenoid is integral with the starter motor.
The solenoid contains a heavy pull-in winding and a light
hold-in winding. Applying battery voltage to the unmarked
'WR wire' connector initially energizes both windings. The
combined action of both windings pulls in the plunger to
cause engagement of the pinion and contact of the
main terminals. The pull-in winding is now shorted-out
leaving the hold-in winding to maintain the plunger position.
Contact of the main terminals energizes the motor.
The roller clutch drive locks up and the engine is cranked.
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Firing of the engine rotates the pinion at high speed.
The roller clutch drive is over-ridden and damaging
high-speed rotation of the armature does not occur.
Driver release of the ignition/starter switch allows the
solenoid plunger to move out under spring pressure.
Contact of the main terminals is broken and disengagement
of the pinion occurs.
1.
2.
3.
4.
5.
6.
7.
8.
Unmarked 'WR wire' connector
Pull-in winding
Hold-in winding
Solenoid battery terminal
IGN. connector for ballast ignition when fitted
Solenoid motor terminal
Brushes and commutator
Field windings
86.60.00 Sheet 5
Triumph TR6 Manual. Part No. 545277 Issue I
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