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).
Test results and specifications for 50-Volt motors.
| Identifier | ExFiles\Box 34\4\ Scan190 | |
| Date | 1st October 1929 | |
| X 2048 To R.{Sir Henry Royce} from EFC. EFC3/ADL1.10.29. 50-VOLT MOTORS. Further to our EFC4/AD23.9.29, one motor is now being sent to you having been duly completed and tested. The main brushes are in no load neutral position and an extra field terminal is provided for convenience of reversal, though on the machine as sent the brushes are arranged with their bevelled tops the way round suitable for right hand rotation looking on the pulley end. Running light in moderately warm condition at 50 volts, the field current is .70 ampere, the armature current 2.75 ampere and the speed 1790 r.p.m. - rather higher than anticipated. Loaded up to .255 B.H.P. on 50 volts at the terminals, the final field current is .61 ampere, the armature current 7.30 ampere and the speed 1850 r.p.m. showing that the speed actually rises slightly with sustained load on account of the heating of the field winding. The overall efficiency at the same B.H.P. is 48.5%. We trust the quantities as arranged will be O.K. for your purpose. A second similar motor is now ready for test and will be sent along in due course. EFC. | ||