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).
Specification document detailing the operational requirements for a dynamo.
| Identifier | ExFiles\Box 168a\3\ img111 | |
| Date | 19th August 1938 guessed | |
| -2- just discernible and not intense sparks, inclined to persist. (5) The dynamo must be free from electro-magnetic noise at all speeds and outputs. Also from undue brush and bearing noise, and mechanical vibration. (6) The insulation of the machine must be such that when fully hot, 70°C. to 80°C it must withstand an applied voltage of 200 volts A.C. and have an insulation resistance not less than 1 megohm. | ||