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).
Page 2 of a technical specification detailing the construction of the frame, field poles, field coils, and brackets for a generator.
| Identifier | ExFiles\Box 23\2\ Scan070 | |
| Date | 4th November 1921 | |
| ROLLS-ROYCE - 2 - 4/11/21 to size, the diameter being held to plus or minus .001". The micarta between the commutator bars is undercut 1/32 to 5/64" insuring good commutation and long brush life, also steady output of the generator. Undercutting of the commutator permits use of self lubricating brushes, which have long life. The final operation is to balance the armature and check for shorts and grounds. 3. FRAME: The frame is made from specially selected seamless steel tubing; the steel used, having high permeability. The frames are cut to length, and the windows punched, after which the frame is finished to size, both inside and outside. After the machining operations are completed, the frame is given a coat of our #97 enamel, which is a dull, black finish and appears similar to that found on telephone equipment. This finish will not chip off. 4. FIELD POLES: Poles are made from extruded steel section. This section is hot rolled and cold drawn. Poles made from extruded section are preferable to those built up from laminations, as the difference in the iron loss with the two constructions is negligible. Laminated poles are difficult to build up and install. The field poles are secured to the frame by two screws. 5. FIELD COILS: It has been our standard practice for years to use bare enameled wire in our field coils, and we have followed this practice in the construction of theRolls-Royce generator. The use of bare enameled wire improves the performance of the machine, inasmuch as the actual space available for copper itself, is greater due to the reduction in insulation space. Coils are so proportioned as to fill the total space available for the field winding. The coils are wound in moulds, and after winding are taped and formed. The coils are then dipped in Sterling varnish and baked for 12 hours. Each coil is given three dips and bakes. A thin strip of bakelite micarta insulates the coil connections from the frame at the coil ends. 6. BRACKETS: Aluminum brackets are standard construction for our 77 BR generator. These brackets are simple flat plates, and so designed that the bracket frame fit comes approximately over the bearing, which arrangement is secured by our punched window construction. Each bracket is secured to the frame by six 10-32 screws. | ||