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).
Instruction sheet discussing electrical output variations related to brush grade, field winding, and commutation.
| Identifier | ExFiles\Box 62\3\ scan0145 | |
| Date | 24th August 1927 | |
| RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 461-8-12-24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. To ......... ...........................................................19__ Order No. PD.58. (5) Customer's No. ......... rather than the shape of brush, our main attempts to overcome it are in the direction of a new grade of brush, and a finer field winding & increased airgap permitting of a wider field span of the armature. It has been suggested that the output varies more with narrow, than with wide brushes. We do not think so. since the wide brush spans a larger portion of the commutator, for a given angle of tilt, the corresponding displacement of the centre of the brush would be more in the case of the wide brush than the narrow brush. As regards variation due to blackening, we believe that commutation was improved by the adoption of the narrow brush, (See PD9/24-8-27) and although, since then, output has been increased from about 10 amperes to at least 12 amperes, and in some cases to about 16 amperes, commutation is at least as good as that obtained with wide brushes. Another cause of variation in output is said to be an alteration in control brush bedding as the result of the armature, for some reason such as an engine back-fire, running backwards. Some considerable time ago we carried out a Cont'd.{John DeLooze - Company Secretary} Signed .................... This Sheet must be filed on completion of the work. | ||