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).
Suggesting improvements for the screening of battery ignition systems on 2/25 tank engines.
| Identifier | ExFiles\Box 163\2\ img014 | |
| Date | 18th November 1932 | |
| V6008 E & Ry. From Hs{Lord Ernest Hives - Chair}/Wst. c.c. to Wor.{Arthur Wormald - General Works Manager} c.c. to F.{Mr Friese} Hs{Lord Ernest Hives - Chair}/Wst.2/MA.18.11.32. X3374 SCREENING OF BATTERY IGNITION ON 2/25 TANK ENGINES. We have now had an opportunity of examining D.Sch.570 and we put forward the various suggestions for your consideration:- (1) Ignition Coil. We notice that the screen for this coil has slots and holes cut in it. This is undesirable as it allows immediate egress of high frequency disturbances from the coil. The high tension terminal also emerges from the screen cover which would also cause almost as much disturbance as if the whole coil were left unscreened. The high tension wire which enters the coil from the top should be beaded at the point where it enters the screen by means of union and nut fixing in a similar way to aero engine magneto practice. This allows an ordinary plain length of rubber cable to enter the coil and thus prevents the close proximity as at present of an earthed fitting to the high tension terminal causing extreme ionisation and possible flash overs due to coronal discharge. The coil case should be ventilated by means of copper gauze windows owing to the larger volume of air surrounding the coil. We suggest for your consideration that an outside primary coil similar to the Delco (a Delco-remy or Lucas coil could be used,) would be a much more simple proposition from the point of view of screening than the attempt that has been made to screen our own inside primary ignition coil. (2) High Tension Distributor. This also should not have slots or holes and also should be bonded direct to the distributor body and not by means of a small flexible earthing wire owing to the fact that if this wire is of any length and happens to get coiled the inductance of it would be so appreciable as to prevent the adequate high frequency earthing of the distributor unit. The wires going into the distributor head are also shown bonded inside. This scheme is | ||