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).
Examination and test report on a Marelli distributor and contact breaker.
| Identifier | WestWitteringFiles\V\2January1931-April1931\ Scan051 | |
| Date | 3rd March 1931 | |
| To-R.{Sir Henry Royce} FROM SFC. C.-Dr.E. C.-WOT.-E.{Mr Elliott - Chief Engineer} C.-Py- HS.{Lord Ernest Hives - Chair} EFC3/AERO.3.31. X.6035. MARELLI DISTRIBUTOR AND CONTACT BREAKER. A Marelli distributor and contact breaker has been examined and tested and the following is a copy of my assistant's report WE.82 in this connection :- "We have now tested in the laboratory a Marelli distributor of the latest design. The design, with the exception of the contact breaker, is almost an exact copy of the Delco Remy so that we presume some arrangement of manufacturing rights exists between the two concerns. A particular exception is that the distributor casing is made in aluminium instead of cast iron as in the Delco Remy. With regard to the contact breaker, this follows on the lines of the well-known Marelli (patented) pivotless contact lever e.g. the moving contact arm consists of a flat steel spring secured at one end and located at the contact end in a bakelite piece which rubs on the cam giving the flat spring an oscillating motion for making and breaking the points. It is claimed for this breaker that extra high speeds are possible owing to the excellent dynamic design. Also the possibility of pivot seizing is obviated. The condenser capacity was found to be very low i.e. .18 m.f. at 18°C. A run of 400 hours at 700 r.p.m. was completed connected up to an R.R. standard coil and ballast on an average voltage of 16.0 with satisfactory results. The condition of the tungsten contacts after this run was very good and better than the Delco Remy or our standard. This in spite of the low condenser capacity. There were no signs of wear on the cam and the contact point setting had only varied about .004". | ||