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).
The specifications for bearings, brush rigging, and terminals.
Identifier | ExFiles\Box 23\2\ Scan071 | |
Date | 4th November 1921 | |
ROLLS-ROYCE - 3 - 4/11/21 7. BEARINGS: Strom ball bearings of the non-separable, entire-ly enclosed type, made by U. E.{Mr Elliott - Chief Engineer} Ball Bearing Co., are used. These are the same type of bearing which are used in other parts of the Rolls-Royce car. The drive end bearing is #304 (20 M M), and the commutator end is #305 (17 M M), both being over size. With the enclosed type bearing, one bearing is secured and the other bear-ing floats, thus compensating for any temperature changes or slight variations encountered in the manufacture. This ball bear-ing construction is the best we know at the present time. Felt washers in the bracket and adjusting nuts, serve to retain the oil in the bearings. These felt washers are stationary and do not rotate. When felt washers are secured to rotating parts, the oil is thrown out of the washer and sometimes trouble results. Before shipment to customer, these bearings are packed in a soft cup grease, which is little effected by changes in temperature, and a few drops of oil every thousand miles, will furnish ample lubrica-tion. Dust proof oilers with hinge snap covers are used. 8. BRUSH RIGGING AND BRUSHES: Swivel type, pressed steel brush holders are so ar-ranged that these can be lifted out through the windows for inspec-tion and replacement of brushes. Morganite EG-3 brushes have been standard on our automobile equipment for years, and we have used these on the 77 BR generator. We notice that this same brush is used on the Smith generator, which is standard equipment on the Rolls-Royce. Each brush is secured to the holder by two small screws. The current passes from brush to the brush holder post through a shunt, and not through bearing between the brush holder and the brush holder stud. A stop is provided to prevent the brush holder from riding on the commutator after brush completely wears down. A steel brush holder operates on a hard phosphour bronze stud which is the best combination we know for such service. The brass brush holder post is soldered to the phosphour bronze stud. A pin in the stud prevents a side motion of the brush holder, at the same time provides easy replacement of brush holder. The brush holder studs are insulated from the frame by bakelite micarta bushings and washers. Two of the brush holders are riveted to the bracket, which construction has been standard with us for years. The brush holder post rests in the micarta duck channel, which in turn rests in a channel milled in the bracket; this construction preventing any rotation of the post. The cross connections between the brushes are carried in directly between the posts through a recess in the bracket over the bearing. 9. TERMINALS: Two armatures and one field terminal are provided. These are all located on the front bracket, and are easily acces-sible. Generator, regulator, and battery connections are shown on our E.D. sketch #56951. | ||