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).
Dynamo failures experienced in light tanks fitted with 20/25 HP engines.
| Identifier | ExFiles\Box 25\1\ Scan031 | |
| Date | 20th September 1935 | |
| + 1080 To Sgt. and Ser. from E.{Mr Elliott - Chief Engineer} E.1/HP.20.S.35. c. Ty. Db.{Donald Bastow - Suspensions} Hx. Rr/Vhs-Ha/Wst. By/RDs-S/JHR-R/Ltd. 20/25 HP. Engines in Light Tanks. Dynamos. With reference to the failures of dynamos which have been experienced, it is evident that these are confined to the Mark '3' Tanks which are wired up differently. In conversation with Mr Lewis we learn that the Mark '3' tank has additional electrical fitments over the Mark '2', such as, quite powerful head lamps, a signalling light, instrument board lighting, gunner's light. This in itself would not lay any more stress on the dynamo but rather the reverse in keeping down battery voltage. It has also been reported that these same tanks have been found with 10 amp. fuses instead of 5 in the field circuit, and this again indicates that some trouble with this fuse blowing has been experienced, which in its turn strongly suggests some basic fault in the arrangement of the electrical system, such as possibly a loose connection between the battery and the dynamo. The result of this would be to throw more electrical load on the dynamo and cause a field fuse to blow. The replacement of the 5 amp fuse with a 10 amp fuse would then cause the failure of the dynamo. From the aforegoing we think it obvious that the blame cannot be laid at the door of the dynamo but rather due to the faulty installation, and as the failures have occurred on more than one tank the fault cannot be accidental but with some basic fault which requires attention on all of the installations concerned. The replacement of the dynamo would only result in repeating the same failure. We are asking | ||