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).
Performance specifications for a third brush controlled dynamo and associated battery system.
| Identifier | ExFiles\Box 51\2\ Scan162 | |
| Date | 19th November 1923 | |
| Contd. -2- EFC {E. Fowler Clarke - Electrical Engineer} 5/T19.11.23. The machine is a single field winding third brush controlled machine and is driven at 1 1/2 times engine speed, the field windings being connefted between the main positive brush and the auxiliary or control and. negative brush, which electrically is more advanced than the main negative brush. When in a quite cold condition the dynamo cuts in at about 600 r.p.m., i.e. 8.2 m.p.h., and the ampere-output rises rapidly to a maximum of 11 at 1400 r.pm. 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 ampere output rises rapidly to a maximum value of 9 amperes at 1400 (handwritten: 1500) r.p.m. i.e. 19 (handwritten: 20) m.p.h.. after which it falls slowly to 5 amperes at 3500 r.p.m. i.e. 47.5 m.p.h. at 82ºC A small photostat curve of ampere output of the dynamo/with and without the ignition current subtracted is herewith attached. Battery. The ampere-hour capacity of the battery provided is 45 to 50 on the 10 hour rate. The battery when fully charged is capable of supplying a current of 105 amperes continuously for 5 minutes. Contd. | ||