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).
Test report on sample tungsten contacts from Messrs Blackwell.
| Identifier | WestWitteringFiles\F\April1921\ Scan77 | |
| Date | 13th April 1921 | |
| RR 300 (120B) (SF 349 24-1-19) MP 200552 91303 ROLLS-ROYCE LIMITED. INSTRUCTIONS. To E.F.C Order No. P.A.75. Re X. 2894. Customer's No. April 13th 1921 Test of Sample Tungsten Contacts from Messrs Blackwell. These contacts have now run for 103 hours, with the following results. The spark points were set at 4.5 m/m to ensure regular sparking. There was practically no sparking at the contacts at the commencement of the run, but after six hours running, a slight sparking started, but sparks on the gaps were quite good. After 40 hrs running, the contacts were examined, and found to be wearing on one side, and the surfaces pitted. Signed Cont'd.{John DeLooze - Company Secretary} This Sheet must be filed on completion of the work. | ||