The correct connection of ignition coils on experimental cars based on polarity markings.
| Identifier | ExFiles\Box 164\5\ img309 | |
| Date | 23th October 1937 | |
| Rm {William Robotham - Chief Engineer} /FD. {Frank Dodd - Bodies} c. to RC {R. Childs} /GJ. 6017A Rm {William Robotham - Chief Engineer} /RC. {R. Childs} 6/JH.23.10.37. re Ignition Coils. All coils fitted to experimental cars should be connected with the primary leads reversed unless marked on the top of the coil with the letter "N". This "N" shows that the polarity of the coil is such that the central electrodes of the sparking plugs connected thereto are made negative. Rm {William Robotham - Chief Engineer} /RC. {R. Childs} | ||
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).