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 instructions for a 20 HP dynamo, focusing on faulty output and commutation.
| Identifier | ExFiles\Box 165\6\ img121 | |
| Date | 14th February 1927 | |
| 20 HP. RR. DYNAMO. INSPECTION FOR FAULTY OUTPUT & COMMUTATION. BRUSH ALIGNMENT. Radial and axial alignment of brush-holders must be correct. See that brushes are - thus [diagram of correctly aligned brush] not thus [diagram of incorrectly aligned brush] Also see that holders run parallel with commutator segments. Brush holders (especially control) must not be more than .090" clear of commutator. See that clearance is fairly even along length of holder. Check holder nuts for tightness. BRUSH & SPRING FREEDOM. Brushes must slide freely in holders with and without spring pressure. If not, clean with petrol. Also clean insides of holders with petrol by means of a rag on a stick. See that springs are not jamming in slots at tops of brushes and holders. There should be a slight amount of side-play. SPRING PRESSURE. Springs must bear on brushes clear of any obstruction. See that no bolts project in the way. Check that brushes have not worn beyond limits of spring travel. See that spring pressures are about 1 lb. on main and 3/4 lb. on control brushes. BRUSH POSITIONS. All flexes must be on outer edges of brushes (away from end-plate) both at brushes and flex terminals. Contd. | ||