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).
Production test results for EAC dynamos with narrower brushes.
| Identifier | ExFiles\Box 70\4\ scan0092 | |
| Date | 19th December 1927 | |
| X.8781 do. PRODUCTION TEST. X.8660. R.R. EAC. DYNAMO. X.8781 do. (NARROWER BRUSH MACHINES) after alteration to 121° C angle | Date. | Dynamo number. | (1) Remarks. | (2)(3)(4) Remarks. | (5) Output at 1250 r.p.m. Amperes (12.5 to 13.5) | (5) Volts (18.0 +- .1) | (6) O.C. Volts at 560 r.p.m. (>= 13.6) | (7)(8)(9)(10) Remarks. | Brush setting angles | |------------|----------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------|---------------------------------------------------------|------------------------|------------------------------------------------|-------------------------|----------------------| | 19-12-27 | GV 85 | OK | Slight brush chattering. | 12.5 | 18.0 | 13.6 | OK | B = 8° | | | | | | | | | 17-53-70 | C = 121° | | 21-12-27 | HU 45 | Excessive clearance between holders; N. 055" C. 048" | Slight chattering on inner brushes. | 12.5 | 18.0 | 13.8 | OK | B = 7.5° | | | | | | | | | 17-45-62 | C = 122.5° | | 28-12-27 | G.V. 65 | Clearance at tops of positive holders exceed .009". Springs too strong:- P I 13 ozs. N.I 16 ozs. O 16 ozs. C.I 12 ozs. 0.14 ozs. Excessive clearance on N holder .050". All springs except I N on the strong side. | OK | 13.1 | 18.0 | 14.0 | Slight brush chatter. | B = 7.5° | | | | | | | | | 18-54-72 | C = 120.5° | | 2-1-28 | G.V. 95 | | OK | 13.1 | 18.0 | 13.3 | Slight brush chatter. | B = 8.5° | | | | | | | | | 17-52-69. | C = 121° | | 3-1-28 | G.V. 55 | OK | OK | 13.4 | 18.0 | 13.6 | OK | B = 7.5° | | | | | | | | | 20-50-70.5 | C = 121.5° | | 16-1-28 | G.V. 75. | Positive and negative springs on the strong side. | OK | 13.0 | 18.0 | 14.26 | OK | B = 7° | | | | | | | | | 18-56-74. | C = 121° | | 6-2-28 | FW 45 | Positive and negative springs too strong. | OK. | 12.6 | 18.0 | 14.20 | OK | B = 7.5° | | | | | | | | | 16-48-64 | C = 121° | | 12.3.26. | | | | | | | | | | ||