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).
Troubleshooting guide for a dynamo, discussing potential faults with voltage, cutouts, and brushes.
| Identifier | ExFiles\Box 47\4\ Scan017 | |
| Date | 18th June 1926 | |
| Contd. -2- EFC5/T18.6.26. the engine should not be increased to more than a moderate speed, as the voltage of the dynamo will then rise unduly. If Mr. Bennion has an electrical friend with a voltmeter up to, say, 25 volts, a voltmeter observation across the outer battery terminals of the dynamo should be taken during this process, and it should be observed that the cutout contacts draw together as indicated by the ammeter when the voltage across the terminals of the dynamo reaches approximately a little above 13 (hot condition). An alternative possibility is that the cutout contact points are dirty enough to prevent making electrical contact although they make mechanical. To ensure that the circuits are correct, a voltmeter observation might be taken between the points of the cutout with everything standing but the charging switch on. This should shew the voltage of the battery. [Stamp: MADE AT CROXLEY] Still a further possibility will be that one dynamo of the five brushes may be prevented from making proper contact with the commutator when hot, by expansion, in which case the trouble would be cured by touching up the side of that particular brush with a file. It should in any case be ascertained that the dynamo brushes are correctly free when hot and bed properly on the commutator, and that the commutator itself is in good condition. It is not likely that the wire circuits are wrong, but more than likely that the fault is either at the dynamo brush or in the cutout itself, and that this is easily curable by a simple correction. Contd. | ||