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).
Temperature observations relating to the melting points of commutator solder and sentinels on 40/50 HP and 20 HP machines.
| Identifier | ExFiles\Box 165\6\ img042 | |
| Date | 2nd December 1926 | |
| X5660 EFC4/T2.12.26. X 8660 X5660 TEMPERATURE OBSERVATIONS RELATING TO COMMUTATOR SOLDER AND SENTINELS MELTING. On the 40/50 HP. machine it has been observed that the commutator solder runs, when the temperature indicated by the mercury thermometer in the usual manner, is 89¼°C. A similar observation taken on the 20 HP. dynamo has also resulted in the same figure. On the 40/50 HP. dynamo it has been observed that our 97°C sentinels melt when the temperature indicated by the mercury thermometer is 83¼°C. On the 20 HP. machine the corresponding figure has been observed to be . We look upon the melting of the 97°C sentinels as being the safety limit. Beyond that point we have 6° in hand before the commutator and solder melts. Further observations are being made upon the extent of exceeding the safety limit on chassis, i.e. on the extent of possibly melting 97° sentinels thereon. EFC. | ||