Triumph SPEED TWIN 1955 User Manual

LUCAS RM 14 A.C.
LIGHTING AND IGNITION
GENERAL DESCRIPTION
Under NORMAL running conditions, electrical energy in the form of rectified A.C.
passes through the battery from the alternator-the rate of charge depending on
the position of the lighting switch. When no lights are in use, the alternator output
is sufficient only to supply the ignit~on coil and to trickle-charge the battery. When
the lighting switch is turned to the "PILOT" or "HEAD" positions, the output
increases proportionately.
Under EMERGENCY starting conditions, trickle-charging continues whilst
ap
ignition performance similar to that from a magneto is obtained. AFTER THE
ENGINE HAS' BEEN STARTED, NORMAL RUNNING IS .RESUMED BY TURNING
THE IGNITI0.N KEY FROM "EMG" to "IGN". IF THE BATTERY MUST BE
REMOZED. THE ENGINE CAN BE RUN WITH THE IGNITION SWITCH
IN THE
"EMG" POSITION PROVIDING THAT THE BATTERY NEGATIVE CABLE (BROWN)
IS EARTHED TO THE FRAME. UNDER THESE CONDITIONS NO LIGHTS ARE
AVAILABLE.
CIRCUIT DETAILS
The alternator stator carries three pairs of series-connected coils, one pair being
permanently connected across the rectifier bridge network. The purpose of this
latter pair is to provide some degree of charging current for the battery whenever
the engine
is running.
.Connections to the remaining coils vary according to the positions of the lighting
and ignition switch controls.
When no lights are in use, the alternator output
from the battery charging coils
is regulated to a minimum by interaction of the rotor
flux set up by current flowing in the short circuited toils.
In the "PILOT" positions these latter coils are disconnected and the regulating fluxes
are consequently reduced. The alternator output therefore increases and com-
pensates for the additional parking light load. In the "HEAD" position, the alternator
output
is further increased by the connection of all three pairs of coils in parallel.
EMERGENCY STARTING (IGNITION SWITCH AT EMG.)
With this circuit the contact breaker is arranged to open when the alternating
current in the windings reaches a maximum. The ignition coil primary winding
and the contact breaker are connected in series. When the contacts separate H.T.
current
is induced in the coil secondary windings, thus producing a spark at the plug.

Triumph SPEED TWIN 1955 Specifications

General

Brand	Triumph
Model	SPEED TWIN 1955
Category	Motorcycle
Language	English