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).
Excessive output and commutation issues with the 20 HP Dynamo, detailing investigation into brush alignment.
| Identifier | ExFiles\Box 51\1\ Scan200 | |
| Date | 25th July 1923 | |
| X4383 To EP. {G. Eric Platford - Chief Quality Engineer} from EFC. {E. Fowler Clarke - Electrical Engineer} BY. {R.W. Bailey - Chief Engineer} " Sft. {Mr Swift} for Mr. Brock. EFC {E. Fowler Clarke - Electrical Engineer} 3/T25.7.23. X.4383 - 20 HP. DYNAMO - COMMUTATION. X4333 With reference to the excessive output of dynamos, in some cases it appears that the machines have passed the production test with a normal output, secured with the control brush within the range provided (or obtained by a slight filing away of the slots), but that after placing on chassis the output has increased so as to become excessive. In other cases, the Production Dept. state that they have been unable to get down to the normal output with the range of control brush obtainable, without some amount of filing. A case of each kind has been investigated by us. Machine No.29 has been returned to us from EP. {G. Eric Platford - Chief Quality Engineer} as a case of excessive output, and on production test, taking the machine just as it was, we found the maximum output to be 13½ amperes. It is probable that this machine was production tested when the maximum was 10 amperes. (Latterly it has been fixed at 12 amps. and now we have dropped it down to 11 amps. - this is after 20 minutes running). Examination of the brush bedding showed inaccuracy of that of the negative brush, clearly due to some disturbance of the brush holder, also excessive circumferential looseness of this brush. The control brush also, though bedding fairly well, had presumably been disturbed, as it was not in correct alignment. Contd. | ||