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).
Inspection and testing procedures for a small shunt dynamo.
| Identifier | ExFiles\Box 168a\3\ img096 | |
| Date | 23th May 1938 | |
| 23.5.38. SPECIFICATION NO. ELC.15.a. INSPECTION AND TESTS OF SMALL SHUNT DYNAMO. Fan machine with rubber buffer drive. Type :- Armature :- 24 slot, 12 conductors, 17 s.w.g. Poles :- Chamfer 15° Air gap .020" - .100". Brush angles :- 8°. Weight 23 lbs. 7 ozs. (without tachometer drive). ---------------- 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 .004" to .009" clearance between brush and holder, and that the spring pressure are suitable. The actual pressure exerted by the springs on the brushes should be 16 ozs. + 2 ozs. (b) The lower edges of the brush holders (near the commutator) are reasonably close to the commutator. (c) That corresponding tips of the brushes are, on the average, exactly 12 commutator segment apart. (d) The brush springs are clear of the sides of the slots of the brush holders, so that the full tensions of the springs 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. Test the springs for cracks, by forcing these back as far as possible, when they should not become cracked. | ||