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).
Analysis of a 22-EX starter failure in France, detailing the distortion of ebonite components.
| Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan246 | |
| Date | 27th May 1929 | |
| R.{Sir Henry Royce} from EFC. c. SG.{Arthur F. Sidgreaves - MD} c. RV. Wor.{Arthur Wormald - General Works Manager} EFC5/D27.5.29. ORIGINAL X.7655. 22-EX STARTER FAILURE IN FRANCE. X.7680 X.8692. The components of the starter system have now been received in the Electrical Experimental Laboratory, and duly examined with a view to arriving at the explanation of the failure. The evidence appears to indicate the following sequence of events :- (1) Distortion of ebonite support of armature operated contact on motor led to this contact being permanently made. The mounting of this contact is now a bakelite moulding and cannot distort sufficiently to produce this effect. (N.B. All the parts of this system which were eventually intended to be bakelite mouldings were machined out of ebonite blocks for the first few experimental sets). (2) Owing partly to distortion of push button switch (also ebonite) due to heat, and partial fracture of carbon contact, the carbon contacts of circuit controlling main switch operating coil made contact and remained on intermittently continuous contact. There is ample detail evidence of this which it is not considered necessary to go into thoroughly. The two items, 1 and 2 together, would be the explanation of the starter attempting violently to engage during normal running on the road. contd. | ||