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).
The cause of a short circuit failure in a starter motor switch, likely due to a flaw in the bakelite moulding.
| Identifier | ExFiles\Box 168a\2\ img044 | |
| Date | 7th August 1931 | |
| X6080 To PN.{Mr Northey} FROM Hs{Lord Ernest Hives - Chair}/HEW. c. Sg.{Arthur F. Sidgreaves - MD} WOT. c. MX.{John H Maddocks - Chief Proving Officer} AP. H.{Arthur M. Hanbury - Head Complaints} c. LT. Chatman. Hs{Lord Ernest Hives - Chair}/HEW2/AD7.8.31. STARTER MOTOR SWITCH OFF CNS-5. With reference to FMS/WT29.7.31, this switch was in such a condition when received, owing to the short circuit, as to make exact diagnosis of the cause of failure rather difficult. From examination it would appear that the cause of the short circuit was due to a breakdown of the bakelite insulating moulding between the contacts. This breakdown has been probably due to a flaw in the moulding allowing carbonization to occur which would then rapidly develop into a low resistance path for the current. This failure is an extremely unlucky one and is the first of its kind within our knowledge that has occurred since these switches were first made. Our moulding plant is thoroughly up-to-date and extreme care is taken to exclude all traces of foreign matter from the mouldings. We should be interested to know if any battery trouble was experienced with this car as the presence of an insulation leak such as the one in question would discharge the battery if the car was left standing any length of time. Hs{Lord Ernest Hives - Chair}/ER. West. | ||