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).
Specification for the inspection and testing of a large shunt dynamo.
| Identifier | ExFiles\Box 168a\3\ img263 | |
| Date | 7th January 1930 | |
| SPECIFICATION OF INSPECTION AND TESTS, OF LARGE SHUNT DYNAMO. Type Armature :- 24 slot, 16 conductors, 18 S.W.G. Poles :- Chamfer 15° Air gap .015" - .100" Brush angle :- 15° Weight - 29.75 lbs. -------------------- Upon receipt of the machine from the assembling benches :- (1) Inspect the brush mechanism and make sure that - (a) All brushes have the necessary freedom, without being unduly slack, i.e. there should be .002" to .009" clearance between brush and holder, and that the spring pressures are suitable. The actual pressures exerted by the springs on the brushes should be 12 ozs +3 ozs. -1 oz. (b) The lower edges of the brush holders (near the commutator) are at the same distance of .031" +10 -5 from the surface of the commutator. (c) That corresponding tips of the brushes are, on the average, exactly 12 commutator segments apart. (d) The brush springs are clear of the sides of the slots of the brush holders, so that the full tensions of the spring are exerted on their respective brushes. Also that these springs are long enough to reach and press on the centre of the brush, and not on the side. | ||