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).
Investigation report on the failure of a Lucas Heater Motor due to overheating.
| Identifier | ExFiles\Box 137\3\ scan0208 | |
| Date | 7th March 1940 | |
| 1158 Rm{William Robotham - Chief Engineer}/WD.{Mr Wood/Mr Whitehead} c. Rm{William Robotham - Chief Engineer}/Col. Rm{William Robotham - Chief Engineer}/EC.3/LL.7.3.40. re LUCAS HEATER MOTOR. We have now completed the investigation on the Lucas Heater Motor which you recently handed to us for examination. The motor failed due to one of the leads to the commutator becoming unsoldered. This was due to excessive heat. Everything points to the motor being stalled whilst connected to the battery, causing an excessive current to flow through the motor windings. It is estimated by the colour of the core that it's temperature has been in the region of 270 deg. C. Most of the insulation varnish has been burnt off the windings and the bakelite brush holder has been badly scorched. Rm{William Robotham - Chief Engineer}/RC.{R. Childs} | ||