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).
Required alterations to the starter switch on Chassis 1 EX.
| Identifier | WestWitteringFiles\C\August1919\ Scan17 | |
| Date | 25th August 1919 | |
| To EFC: from E.{Mr Elliott - Chief Engineer} Copy to CJ. " " DN. " " EH. " " BY.{R.W. Bailey - Chief Engineer} " " EH. ORIGINAL. 25 AUG 1919 RECEIVED RE ELECTRICAL EQUIPMENT - CHASSIS 1 EX. 2565 (Strikethrough) x.3034 x.3082 Referring to the starter switch on chassis 1 EX. Mr. Royce noticed that the spark occurred when the switch broke, at the main contact instead of at the carbon contact. This led to a practical examination of the mechanism, following on which Mr. Royce directs me to send you the following points which he would like altered:- (1) Although the switch as adjusted on 1 EX. was timed to break correctly, the copper brush of the main contact upset the timing by following the armature when the release occurred, and was therefore in contact after the carbons had broken. The fault is that the brush is too flexible. Actually, when the contact surface of the brush was inspected, the longer leaves were seen to shew distinct signs of burning. Mr. Royce considers that the brush should be altered to have somewhat thicker leaves, with less space in between, that is to say, spacing plates should be thinner. This should give a brush of less flexibility, which will be more suitable for this switch. Referring again to the timing of the switch, this was re-adjusted on chassis 1 EX. with the carbon contact breaking still later. This, you will observe, is a safer practice where a certain amount of flexibility of the main contact brush has to be reckoned with. (2) It was noted that copper carbons had been used for the secondary contact. Mr. Royce wishes pure carbon to be used here to avoid trouble due to oxidation caused by the breaking spark. Mr. Royce thinks there is no necessity for metal to be included at all in the composition of the secondary brushes. (3) The boss on the inside of the brush stamping should be definitely cut back clear of the brush so as to ensure that the brush blades shall always be free and not scraping or touching on the boss. (Contd.) [Handwritten notes:] Next to (1): Done ✓ Next to the second paragraph of (1): ✓ Next to (2): ✓ Next to (3): 2 x Near top right reference: 4-6 W H S32V (200 J) (R'D' 409 S6-+-1A) BW' S1120U3? | ||