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).
Letter from Bosch Limited explaining the potential causes of a dynamo failure, specifically melted and welded contacts.
| Identifier | ExFiles\Box 60\4\ Scan129 | |
| Date | 22th December 1931 | |
| TELEPHONE: SHEPHERD'S BUSH 2080 (4 LINES) TELEGRAMS: ELECBRIGHT, ACT, LONDON BOSCH LIMITED HEAD OFFICES: LARDEN ROAD, ACTON LONDON, W.3. DIRECTORS: P. J.{Mr Johnson W.M.} A.{Mr Adams} CLAUSEN (British of Danish Origin) E.{Mr Elliott - Chief Engineer} SCHWER (German) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} JONES H.{Arthur M. Hanbury - Head Complaints} P. BAZELEY GLASGOW: 222, BOTHWELL ST.{Capt. P. R. Strong}, C.2 PHONE: CENTRAL 3154 TELEGRAMS: ELECBRIGHT, GLASGOW SOLE AGENTS IN GT. BRITAIN & IRELAND FOR BOSCH PRODUCTS MADE BY ROBERT BOSCH A.{Mr Adams} G.{Mr Griffiths - Chief Accountant / Mr Gnapp} STUTTGART MAGNETOS - DYNAMOS - ELECTRIC STARTERS - SPARKING PLUGS - BICYCLE LIGHTING SETS - HORNS - HEADLAMPS - INJECTION PUMPS - NOZZLES - ACCESSORIES - LUBRICATORS JWH/FW Messrs. Rolls-Royce Ltd., DERBY Ref: Hs{Lord Ernest Hives - Chair}/Wst.3/AD December 22nd, 1931. Dear Sirs, We are in receipt of your letter of the 17th inst., and thank you for the information contained therein. The cause of the failure of the dynamo is due to the lower contacts of the regulator being melted away, and the upper contacts becoming welded together. The cause of the lower contacts being melted away could be due to running the dynamo with the field resistance coil open circuited. In these circumstances the lower contacts would be destroyed in a few minutes. With regard to the welding of the upper contacts this could be caused by a short-circuit between the regulator angle piece and the frame of the dynamo. We would ask you, therefore, if you would be kind enough to make investigations at your end to ascertain whether it is possible that you have run the dynamo with the cable of the field resistance disconnected and that there has also been, not necessarily at the same time, a short circuit between the regulator angle piece and the frame. If you find that this has occurred whilst testing, then we need not look any further for an explanation. Adverting to your letter of December 15th, ref: Hs{Lord Ernest Hives - Chair}/Wst/s/MA, when you asked - Handwritten: X4562 | ||