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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Guide for troubleshooting electrical earth faults in the ignition and battery systems.

Identifier  ExFiles\Box 61\2\  scan0153
Date  28th October 1919 guessed
  
Contd. -19-

If the system is O.K. as regards the above, and a fuse foes when the battery ignition switch on the steering column is put on, this is due to an earth in one of the connections :-
(a) Steering column switch to lower insulated terminal on junction box.
(b) Lower insulated terminal on junction box to bottom terminal on coil anf ballast.

If the fuse goes when the push button switch is depressedn this is due to an earth in one of the connections :-
(a) Push button switch to actuator box.
(b) " " main switch.

To trace an earth somewhere on the remaining portion of the system not included in the above proceed as follows:-
First remove central high tension connection from battery ignition distributor and earth this, to avoid any possibility of engine being inadvertently started.
Then set ignition switch on steering column to "B" position and crank engine, if necessary, until current through ignition coil is indicated on ammeter.
If now the positive fuse on junction box be removed, the current should be stopped. If, however, the current continues at the same value ( 2 amperes ) there is an earth somewhere on one of the following positive leads :-
(a) Switchbox + to lamps.
(b) Switchbox + to dynamo+ .
(c) Junction box + to switchbox+ .
(d) Junction box + to actuator box.
(e) Battery + to junction box +.
(f) Battery + to main switch (heavy cable.)

which should be traced by disconnecting these in this order, and rectified.

Contd
  
  


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