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).
Tests measuring the loss of potential difference (voltage) in headlamp wiring on experimental cars.
| Identifier | ExFiles\Box 168b\2\ img223 | |
| Date | 6th March 1931 | |
| X6082. To Wor.{Arthur Wormald - General Works Manager} from EFC. (3 copies) EFCB/AD6.3.31. X.6082. LOSS OF P.D. IN HEAD LAMP WIRING. X.1357 As a result of PN{Mr Northey}1/PH10.2.31 I asked my assistant to make tests of the loss of P.D. on experimental cars in three different circumstances (1) 60 watt head lamps lighted from battery. (2) 48 watt head lamps lighted from battery. (3) 60 watt head lamps lighted whilst dynamo is running on peak output. In the case of one car 20-EX, this was fitted with the central lamp switching scheme with Lucas foot switch with the necessary extra wiring. In the case of the other car 14-EX, this was not so fitted and would therefore (in the absence of such auxiliaries) represent standard wiring. On 20-EX with 60 watt head lamps lighted from the battery the losses of P.D. on the feed wire were :- (a) Between the battery positive terminal and the main emergency fuse .3 volt. (b) Between the main fuse and the head lamp fuse .4 volt. (c) Between the head lamp fuse and either head lamp .7 volt. making a total loss of 1.4 volt. Similar figures in the case of the 48 watt head lamps were correspondingly less namely, approximately .2, .3 and .6 volt respectively, totalling 1.1 volt. With the dynamo charging on peak output and with 60 watt lamps, the loss (b) Between the main fuse and the head lamp fuse was .2 and | ||