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).
Instructions detailing the testing of various dynamo armatures to evaluate performance and noise levels.
| Identifier | ExFiles\Box 165\6\ img103 | |
| Date | 29th June 1920 | |
| RR 238 (150 BKS.) (SH57 29-6-20.) MP 224358 ROLLS-ROYCE LTD. INSTRUCTIONS. To _________ Order No. _________ Customer's No. 2. neutral position, the control brush was re-set to adjust the output to the correct peak value. A 28 slot armature with axially cut slots has been made with a view to testing whether the number of slots would be sufficiently effective to silence a straight-slot machine. A brief run however revealed considerable hum although the noise was not so loud as that produced by a 29 slot straight-slot armature. A 20 h.p dynamo F9V recently received from production, fitted with a 28 slot armature gave a curve similar to that of No 1143 machine (with 29 slot armature) the control brush being set at the standard angle of 121°. Signed _________ (cont-d) This Sheet must be filed on completion of the work. | ||