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).
Data on the Goshawk electrical system, detailing the dynamo and starter motor.
| Identifier | ExFiles\Box 51\2\ Scan107 | |
| Date | 5th December 1922 | |
| A4338 To SFT. {Mr Swift} from EFC. {E. Fowler Clarke - Electrical Engineer} DATA OF GOSHAWK ELECTRICAL SYSTEM. DYNAMO. Carcase diameter 5" Weight of dynamo inclusive of coupling 21 lbs. When in a quite cold condition the dynamo cuts in at 600 r.p.m. i.e. 8.2 m.p.h. and the ampere output rises rapidly to a maximum value of 11 amperes at 1400 r.p.m., i.e. 19 m.p.h., after which it falls slowly to 6 amperes at 3500 r.p.m., i.e. 47.5 m.p.h. In a fully hot condition the dynamo cuts in at 690 r.p.m. i.e. 9.4 m.p.h. The ampereoutput rises rapidly to a maximum value of 8 1/2 at 1400 r.p.m., i.e. 19 m.p.h., after which it falls slowly to 5 amperes at 3500 r.p.m., i.e. 47.5 m.p.h. The dynamo runs at 1 1/2 times engine speed. It is of the single field winding third brush control type. STARTER MOTOR. The weight of the starter motor without Bendix is 17 lbs. Carcase diameter 4.5" Reduction ratio 8.4 The starter motor when rolling the engine moderately cold takes from the battery a current of 115 amps. at 9.7 volts on the motor terminals, and turns the engine at 110 r.p.m., the motor itself operating at a torque of 50 lb-inches. N.B. The exact speed of rolling the engine of course depends a great deal on the temperature condition of the engine. | ||