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 failure of a dynamo lighting system caused by a sticking automatic cut-out switch, leading to battery discharge.
| Identifier | ExFiles\Box 46\3\ Scan281 | |
| Date | 10th December 1919 | |
| X.3014/b (3) Ck.{Mr Clark} from EP.{G. Eric Platford - Chief Quality Engineer} c. to Bn.{W.O. Bentley / Mr Barrington} c. to EH. EP{G. Eric Platford - Chief Quality Engineer}1/F10.12.19. X.3014/b.RE. FAILURE OF DYNAMO LIGHTING SYSTEM. X 8440 X.664 / X 8440 Further to my conversation with you on this matter, I am still having trouble of the automatic cut-out sticking and allowing the batteries to discharge through the dynamo when the dynamo is running below its "charging speed". The failure appears to take place after the car has been in use for some time. I am anxious for this matter to receive attention, as I feel that although the cars may be alright when tested here, they will develop this trouble after they have been in the customers' hands for some time. The failure is very serious, as it means complete discharge of the batteries. On a special car on which I was testing for this fault, I noticed that the switchbox became warm and the cut-out switch stuck and only released itself by knocking the dashboard. On running the engine with the switch cover off, I noticed that for a considerable range of dynamo speed about the cutting-in and cutting-off position, sparking was continually taking place at the cut-out switch. I also found that the cause of the sticking appeared to be due to fused copper or other metal which had taken place at the contacts, evidently caused by the sparking, and that this had caused the brush to stick in position. After the contacts had been cleaned, the cut-out worked quite satisfactorily, but the sparking did not cease. I consider this is a matter which requires your investigation, and possibly you may be able to obtain a carbon make and break for this switch. I also think that the switch itself could be better fitted so as to have a better surface contact. If you have any suggestions or easy improvements which can be made, please let us know, so that we can arrange for such to be embodied on existing cars, and if necessary, deal with any complaints which we may receive in connection with this matter. [Signature] EP.{G. Eric Platford - Chief Quality Engineer} | ||